IndietroCollege Algebra Exam 1: Step-by-Step Study Guidance
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Q1. Solve the linear equation for x: 86 = 9x - 4
Background
Topic: Solving Linear Equations
This question tests your ability to solve a basic linear equation for the variable x.
Key Terms and Formulas
Linear equation: An equation of the form .
To solve for x, isolate x on one side of the equation.
Step-by-Step Guidance
Start by adding 4 to both sides of the equation to move the constant term.
After simplifying, you will have an equation where 9x is equal to a number.
Divide both sides by 9 to solve for x.
Try solving on your own before revealing the answer!
Final Answer:
Add 4 to both sides: gives .
Divide both sides by 9: .
Q2. Solve for x:
Background
Topic: Solving Linear Equations with Variables on Both Sides
This question tests your ability to simplify and solve linear equations where variables appear on both sides.
Key Terms and Formulas
Distributive property:
Combine like terms and isolate x.
Step-by-Step Guidance
Distribute the -2 on the right side: .
Simplify both sides by combining like terms.
Move all terms containing x to one side and constants to the other.
Solve for x by isolating it.
Try solving on your own before revealing the answer!
Final Answer:
After distributing and simplifying, you get .
Combine like terms and solve: .
Q3. Simplify: and write your answer in the form .
Background
Topic: Complex Numbers (Multiplication)
This question tests your ability to multiply complex numbers and express the result in standard form.
Key Terms and Formulas
Complex number: , where
Use the distributive (FOIL) method to multiply.
Step-by-Step Guidance
Apply the distributive property (FOIL): Multiply each term in the first parenthesis by each term in the second.
Remember that when simplifying.
Combine real and imaginary parts to write in form.
Try solving on your own before revealing the answer!
Final Answer:
Multiplying out: .
Combine like terms and use to simplify: .
Q4. Factor the polynomial:
Background
Topic: Factoring Difference of Squares
This question tests your ability to recognize and factor expressions of the form .
Key Terms and Formulas
Difference of squares:
Step-by-Step Guidance
Identify and such that and .
Write the expression as a difference of squares.
Apply the factoring formula for difference of squares.
Try solving on your own before revealing the answer!
Final Answer:
Q5. Factor the polynomial:
Background
Topic: Factoring Quadratic Trinomials
This question tests your ability to factor a quadratic expression of the form .
Key Terms and Formulas
Quadratic trinomial:
Factoring by grouping or trial and error for integer factors.
Step-by-Step Guidance
Multiply and to find the product.
Find two numbers that multiply to and add to .
Rewrite the middle term using these two numbers and factor by grouping.
Try solving on your own before revealing the answer!
Final Answer:
Find numbers that multiply to and add to (which are and ), then factor by grouping.
Q6. Factor the polynomial:
Background
Topic: Factoring Perfect Square Trinomials
This question tests your ability to recognize and factor perfect square trinomials.
Key Terms and Formulas
Perfect square trinomial:
Step-by-Step Guidance
Identify and such that and .
Check if the middle term is .
If so, write the trinomial as a squared binomial.
Try solving on your own before revealing the answer!
Final Answer:
because .
Q7. Solve the quadratic equation by factoring:
Background
Topic: Solving Quadratic Equations by Factoring
This question tests your ability to rearrange and factor a quadratic equation to find its solutions.
Key Terms and Formulas
Quadratic equation:
Zero product property: If , then or .
Step-by-Step Guidance
Move all terms to one side to set the equation to zero.
Factor the resulting quadratic expression.
Set each factor equal to zero and solve for x.
Try solving on your own before revealing the answer!
Final Answer: or
Rewriting: , which factors to .
So, or .
Q8. Solve the quadratic equation by using the square root property:
Background
Topic: Solving Quadratic Equations Using the Square Root Property
This question tests your ability to isolate and apply the square root property.
Key Terms and Formulas
Square root property: If , then
Step-by-Step Guidance
Divide both sides by 4 to isolate .
Take the square root of both sides, remembering to include both the positive and negative roots.
Try solving on your own before revealing the answer!
Final Answer:
Divide by 4: . Then .
Q9. Use the quadratic formula to solve:
Background
Topic: Quadratic Formula
This question tests your ability to use the quadratic formula to solve a quadratic equation.
Key Terms and Formulas
Quadratic formula:
For
Step-by-Step Guidance
Identify , , and from the equation.
Plug these values into the quadratic formula.
Calculate the discriminant .
Set up the expression for using the formula, but do not compute the final value yet.
Try solving on your own before revealing the answer!
Final Answer: , or
Here, , , . The discriminant is .
So, .
Q10. Solve the rational equation and state what values of x make the denominators zero:
Background
Topic: Rational Equations and Domain Restrictions
This question tests your ability to solve equations involving rational expressions and to identify excluded values.
Key Terms and Formulas
Rational equation: An equation involving fractions with variables in the denominator.
Excluded values: Values that make any denominator zero.
Step-by-Step Guidance
Identify values of x that make any denominator zero.
Find a common denominator and rewrite the equation without fractions.
Solve the resulting linear equation for x.
Try solving on your own before revealing the answer!
Final Answer: ; excluded values are and
Denominators are zero when or .
Solving the equation gives (which is allowed).
Q11. Solve the radical equation and check all proposed solutions:
Background
Topic: Solving Radical Equations
This question tests your ability to solve equations involving square roots and to check for extraneous solutions.
Key Terms and Formulas
Radical equation: An equation in which the variable is under a radical sign.
Extraneous solution: A solution that does not satisfy the original equation.
Step-by-Step Guidance
Square both sides to eliminate the square root.
Rearrange the resulting quadratic equation to standard form.
Solve the quadratic equation for x.
Check each solution in the original equation to ensure it is valid.
Try solving on your own before revealing the answer!
Final Answer:
Squaring both sides gives . Rearranged: .
Factoring gives , so or . Only $x = 11$ checks in the original equation.
Q12. Solve the absolute value equation or indicate that the equation has no solution:
Background
Topic: Absolute Value Equations
This question tests your ability to solve equations involving absolute values.
Key Terms and Formulas
Absolute value: if , if
To solve , set and .
Step-by-Step Guidance
Subtract 7 from both sides to isolate the absolute value.
Set up two equations: and .
Solve each equation for x.
Try solving on your own before revealing the answer!
Final Answer: or
Subtract 7: . So or .
Solving gives or .
Q13. Solve the linear inequality and express the solution in interval notation:
Background
Topic: Linear Inequalities
This question tests your ability to solve inequalities and express the solution set in interval notation.
Key Terms and Formulas
Linear inequality: An inequality involving a linear expression.
When multiplying or dividing both sides by a negative, reverse the inequality sign.
Step-by-Step Guidance
Add to both sides to collect x terms on one side.
Simplify and isolate x.
Express the solution in interval notation.
Try solving on your own before revealing the answer!
Final Answer: ; interval notation:
After simplifying, .
Interval notation: .
Q14. Solve the absolute value inequality and express the solution in interval notation:
Background
Topic: Absolute Value Inequalities
This question tests your ability to solve inequalities involving absolute values and express the solution set in interval notation.
Key Terms and Formulas
For , the solution is .
Step-by-Step Guidance
Add 9 to both sides to isolate the absolute value.
Set up the compound inequality based on the absolute value property.
Solve for x in the resulting inequality.
Express the solution in interval notation.
Try solving on your own before revealing the answer!
Final Answer: ; interval notation:
Add 9: . So .
Solving gives .
Q15 (Extra Credit). Divide and write your answer in the form :
Background
Topic: Division of Complex Numbers
This question tests your ability to divide complex numbers and express the result in standard form.
Key Terms and Formulas
To divide by a complex number, multiply numerator and denominator by the conjugate of the denominator.
Conjugate: If , the conjugate is .
Step-by-Step Guidance
Multiply numerator and denominator by the conjugate of , which is .
Expand both numerator and denominator using distributive property.
Simplify the denominator using .
Write the result in form.
Try solving on your own before revealing the answer!
Final Answer:
Multiplying numerator and denominator by gives .
After simplifying, the answer is .