IndietroIntermediate Algebra Exam 1 Study Guidance (Ch 2 & 3)
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Q1. Translate the sentence: "x is 25% of 200." Which equation correctly represents this?
Background
Topic: Percent Problem Solving
This question tests your ability to translate a verbal statement involving percentages into an algebraic equation.
Key Terms and Formulas:
Percent: A way to express a number as a fraction of 100.
"of" in math usually means multiplication.
25% as a decimal is 0.25.
Step-by-Step Guidance
Identify the unknown: Let represent the value we are solving for.
Translate "25% of 200" into mathematical terms: .
Set up the equation: .
Check the answer choices to see which matches this setup.
Try solving on your own before revealing the answer!
Final Answer: x = 0.25 × 200
The correct equation is . This directly translates the sentence "x is 25% of 200."
Q2. Why does the equation |x| = -3 have no real solutions?
Background
Topic: Absolute Value Equations
This question tests your understanding of the definition and properties of absolute value.
Key Terms and Formulas:
Absolute value: is always non-negative (never less than zero).
There is no real number whose absolute value is negative.
Step-by-Step Guidance
Recall the definition: represents the distance from zero, which is always zero or positive.
Consider what it would mean for to have a solution.
Ask: Is there any real number such that its absolute value is negative?
Try solving on your own before revealing the answer!
Final Answer: Because absolute value represents distance, which cannot be negative, no real x has distance -3 from zero.
The correct answer is: b. Because absolute value represents distance, which cannot be negative, no real x has distance -3 from zero.
Q3. Solve the inequality: x - 7 > 2
Background
Topic: Linear Inequalities in One Variable
This question tests your ability to solve a basic linear inequality.
Key Terms and Formulas:
Linear inequality: An inequality involving a linear expression.
To solve, isolate the variable using inverse operations.
Step-by-Step Guidance
Start with the inequality: .
Add 7 to both sides to isolate .
Simplify the right side after addition.
Try solving on your own before revealing the answer!
Final Answer: x > 9
After adding 7 to both sides, you get .
Q4. If -2x < 6, what is the correct solution for x after isolating the variable?
Background
Topic: Absolute Value Inequalities / Linear Inequalities
This question tests your ability to solve inequalities, especially when dividing by a negative number.
Key Terms and Formulas:
When you multiply or divide both sides of an inequality by a negative number, you must reverse the inequality sign.
Step-by-Step Guidance
Start with .
Divide both sides by to solve for .
Remember to reverse the inequality sign when dividing by a negative.
Try solving on your own before revealing the answer!
Final Answer: x > -3
Dividing both sides by -2 and reversing the inequality gives .
Q5. Translate: "There are eight more nickels than dimes," if d = number of dimes and n = number of nickels.
Background
Topic: Mixture Problem Solving / Translating Sentences to Equations
This question tests your ability to write an equation based on a verbal statement about quantities.
Key Terms and Formulas:
"Eight more" means you add 8 to the number of dimes to get the number of nickels.
Step-by-Step Guidance
Let be the number of dimes and the number of nickels.
"Eight more nickels than dimes" means nickels = dimes + 8.
Write this as an equation: .
Try solving on your own before revealing the answer!
Final Answer: n = d + 8
The correct translation is .
Q6. Solve: 4(x - 2) = 3x + 5. Which value of x satisfies the equation?
Background
Topic: Solving Linear Equations
This question tests your ability to solve a linear equation for the variable x.
Key Terms and Formulas:
Distributive property:
Combine like terms and isolate x.
Step-by-Step Guidance
Expand the left side: .
Set the equation: .
Subtract from both sides to get all x terms on one side.
Add 8 to both sides to isolate x.
Try solving on your own before revealing the answer!
Final Answer: x = 13
After simplifying and isolating x, you find .
Q7. Which symbol denotes the intersection of sets A and B?
Background
Topic: Set Operations and Compound Inequalities
This question tests your knowledge of set notation, specifically the symbol for intersection.
Key Terms and Formulas:
Intersection: The set of elements common to both sets.
Symbol:
Step-by-Step Guidance
Recall that intersection means elements in both sets.
Identify the symbol for intersection among the choices.
Try solving on your own before revealing the answer!
Final Answer: A ∩ B
The intersection of sets A and B is denoted by .
Q8. Which phrase signals you should introduce a variable? Sentence: "The number of apples a student picks."
Background
Topic: Translating Sentences to Equations
This question tests your ability to identify the unknown quantity in a word problem.
Key Terms and Formulas:
Unknown quantity: The part of the sentence that is not specified and needs a variable.
Step-by-Step Guidance
Look for phrases that describe an unknown amount.
"The number of apples" is the quantity we don't know and should represent with a variable.
Try solving on your own before revealing the answer!
Final Answer: "The number" or "the number of apples"
This phrase signals the unknown quantity to represent with a variable.
Q9. Simplify and solve: -3(2x + 5) + 4x = 7
Background
Topic: Solving Linear Equations
This question tests your ability to use the distributive property and combine like terms to solve for x.
Key Terms and Formulas:
Distributive property:
Combine like terms and isolate x.
Step-by-Step Guidance
Expand to .
Add to get .
Combine like terms: .
Add 15 to both sides to isolate the x term.
Try solving on your own before revealing the answer!
Final Answer: x = -11
After simplifying and isolating x, you find .
Q10. The formula for the volume of a triangular prism is V = (1/2)bhL. If b = 6 cm, h = 8 cm, and L = 10 cm, compute V.
Background
Topic: Formulas
This question tests your ability to substitute values into a geometric formula and compute the result.
Key Terms and Formulas:
Volume of a triangular prism:
Step-by-Step Guidance
Write the formula: .
Substitute , , into the formula.
Multiply and first, then multiply by .
Multiply by to get the final volume.
Try solving on your own before revealing the answer!
Final Answer: 240 cm³
Substituting the values gives cm³.
Q11. Given 5x - 10y ≤ 20, write the boundary line in slope-intercept form.
Background
Topic: Linear Inequalities in Two Variables
This question tests your ability to rewrite a linear equation in slope-intercept form ().
Key Terms and Formulas:
Slope-intercept form:
Step-by-Step Guidance
Start with (boundary line).
Subtract from both sides: .
Divide both sides by to solve for .
Try solving on your own before revealing the answer!
Final Answer: y = (1/2)x - 2
After rearranging, the boundary line is .
Q12. Which mapping diagram corresponds to the ordered pairs (1, 2), (3, 4), and (1, 5)?
Background
Topic: Introduction to Relations and Functions
This question tests your understanding of mapping diagrams and how ordered pairs are represented.
Key Terms and Formulas:
Mapping diagram: Shows how each input (x) is paired with an output (y).
Step-by-Step Guidance
List the ordered pairs: (1, 2), (3, 4), (1, 5).
Notice that 1 is paired with both 2 and 5, and 3 is paired with 4.
Look for a diagram where 1 points to both 2 and 5, and 3 points to 4.
Try solving on your own before revealing the answer!
Final Answer: A diagram where 1 points to 2 and 5, and 3 points to 4.
This matches the mapping for the given ordered pairs.
Q13. A line passes through (3, 5) and (0, -2). What is the y-intercept?
Background
Topic: Slope-Intercept Form
This question tests your ability to find the y-intercept from two points on a line.
Key Terms and Formulas:
y-intercept: The value of y when x = 0.
Step-by-Step Guidance
Recall that the y-intercept is the y-value when x = 0.
Look at the given points: (3, 5) and (0, -2).
Identify which point has x = 0.
Try solving on your own before revealing the answer!
Final Answer: -2
The y-intercept is -2, from the point (0, -2).
Q14. What does the notation f(x) represent in the context of functions relating x and y?
Background
Topic: Function Notation
This question tests your understanding of function notation and its meaning.
Key Terms and Formulas:
Function notation: means "the value of the function f at x" or "the output y for input x".
Step-by-Step Guidance
Recall that is read as "f of x".
It represents the output value when x is the input.
It does not mean multiplication or a new variable.
Try solving on your own before revealing the answer!
Final Answer: The output y corresponding to the input x
represents the output value for the input x in the function f.
Q15. For 4x + 2y = 8, if x = 1, what is the corresponding y and which point do you plot?
Background
Topic: Graph Linear Equations Using Intercepts
This question tests your ability to substitute a value for x and solve for y in a linear equation.
Key Terms and Formulas:
Substitute x = 1 into the equation and solve for y.
Step-by-Step Guidance
Start with .
Substitute into the equation: .
Simplify and solve for y.
Try solving on your own before revealing the answer!
Final Answer: (1, 2)
When , , so the point to plot is (1, 2).
Q16. What is the best definition of an ordered-pair solution to a two-variable linear equation?
Background
Topic: Graph Linear Equations in Two Variables
This question tests your understanding of what it means for an ordered pair to be a solution to a linear equation.
Key Terms and Formulas:
Ordered pair:
Solution: When substituted into the equation, both sides are equal.
Step-by-Step Guidance
Recall that a solution to a linear equation in two variables is a pair .
Substitute into the equation to check if it makes the equation true.
The correct definition will mention both substitution and equality.
Try solving on your own before revealing the answer!
Final Answer: An ordered pair (x, y) that, when substituted into the equation, makes both sides equal; it corresponds to the single point with coordinates x and y on the coordinate plane.
This is the precise definition of an ordered-pair solution.
Q17. Find the slope of the line through (4, -2) and (1, 4) using the slope formula.
Background
Topic: Slope of a Line
This question tests your ability to use the slope formula to find the slope between two points.
Key Terms and Formulas:
Slope formula:
Step-by-Step Guidance
Label the points: and .
Plug the values into the slope formula: .
Simplify the numerator and denominator separately.
Try solving on your own before revealing the answer!
Final Answer: -2
The slope is .
Q18. Which statement correctly describes the roles of the x-axis and y-axis in the Cartesian plane?
Background
Topic: The Rectangular Coordinate System
This question tests your understanding of the axes in the Cartesian (rectangular) coordinate system.
Key Terms and Formulas:
x-axis: Horizontal axis
y-axis: Vertical axis
Step-by-Step Guidance
Recall that the x-axis runs left to right (horizontal) and the y-axis runs up and down (vertical).
The origin is where the axes intersect (0, 0).
Negative and positive values are included on both axes.
Try solving on your own before revealing the answer!
Final Answer: The x-axis is horizontal and represents left–right movement, while the y-axis is vertical and represents up-down movement. Together, they form the rectangular coordinate system.
This is the correct description of the axes in the Cartesian plane.
Q19. Write the equation of the line in point-slope form with slope m = 3 passing through (4, -1).
Background
Topic: Point Slope Form
This question tests your ability to write the equation of a line given a point and a slope.
Key Terms and Formulas:
Point-slope form:
Step-by-Step Guidance
Identify the point and the slope .
Plug these values into the point-slope formula: .
Simplify to .
Try solving on your own before revealing the answer!
Final Answer: y + 1 = 3(x - 4)
This is the equation in point-slope form for the given point and slope.