IndietroChapter 1 Test Review: Equations and Inequalities (Precalculus Guidance)
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Q1. Solve the absolute value inequality:
Background
Topic: Absolute Value Inequalities
This question tests your ability to solve inequalities involving absolute values and express the solution in interval notation.
Key Terms and Formulas
Absolute value: represents the distance of from zero on the number line.
For , the solution is .
Step-by-Step Guidance
Recognize that means the expression inside the absolute value is less than 28 units from zero.
Rewrite the inequality as a compound inequality: .
Add 7 to all parts of the inequality to isolate .
Express the solution in interval notation once you have isolated.
Try solving on your own before revealing the answer!
Final Answer:
Adding 7 to each part gives , so the solution in interval notation is .
Q2. Solve and check the linear equation:
Background
Topic: Linear Equations
This question tests your ability to solve linear equations and check your solution by substitution.
Key Terms and Formulas
Linear equation: An equation of the form .
Combine like terms and isolate .
Step-by-Step Guidance
Expand the parentheses: .
Combine like terms to simplify the equation.
Isolate by subtracting or adding terms as needed.
Once you solve for , substitute back into the original equation to check your answer.
Try solving on your own before revealing the answer!
Final Answer:
After simplifying and solving, . Substituting back confirms the solution.
Q3. Solve the radical equation:
Background
Topic: Radical Equations
This question tests your ability to solve equations involving square roots and check for extraneous solutions.
Key Terms and Formulas
Radical equation: An equation with a variable inside a root.
To solve, isolate the radical and then square both sides.
Step-by-Step Guidance
Isolate the square root: .
Square both sides to eliminate the radical: .
Rearrange the equation to standard quadratic form: .
Factor or use the quadratic formula to solve for .
Check each solution in the original equation to ensure it is valid (no extraneous solutions).
Try solving on your own before revealing the answer!
Final Answer:
After solving and checking, is the valid solution.
Q4. Divide and express in standard form:
Background
Topic: Complex Numbers
This question tests your ability to divide complex numbers and express the result in standard form .
Key Terms and Formulas
Standard form:
To divide, multiply numerator and denominator by the conjugate of the denominator.
Conjugate: For , the conjugate is .
Step-by-Step Guidance
Identify the conjugate of the denominator: .
Multiply numerator and denominator by the conjugate.
Expand and simplify the numerator and denominator.
Express the result in the form .
Try solving on your own before revealing the answer!
Final Answer: , or
Multiplying by the conjugate and simplifying gives the standard form.
Q5. After a 90% reduction, you purchase a washing machine on sale for $76. What was the original price?
Background
Topic: Linear Models and Applications
This question tests your ability to set up and solve a percent reduction word problem.
Key Terms and Formulas
Percent reduction: Sale price = Original price × (1 - reduction rate)
Let be the original price.
Step-by-Step Guidance
Let be the original price.
Write the equation: .
Solve for by dividing both sides by .
Try solving on your own before revealing the answer!
Final Answer:
The original price was $760. The sale price is 10% of the original price.
Q6. Solve using the square root property:
Background
Topic: Square Root Property
This question tests your ability to solve quadratic equations using the square root property.
Key Terms and Formulas
Square root property: If , then .
Step-by-Step Guidance
Take the square root of both sides: .
Solve for by adding 8 to both sides.
Try solving on your own before revealing the answer!
Final Answer: or
Both and satisfy the equation.
Q7. Solve the linear inequality:
Background
Topic: Linear Inequalities
This question tests your ability to solve linear inequalities and express the solution in interval notation.
Key Terms and Formulas
Linear inequality: An inequality involving a linear expression.
Combine like terms and isolate .
Step-by-Step Guidance
Expand the left side: .
Write the inequality: .
Move all terms involving to one side and constants to the other.
Solve for and express the solution in interval notation.
Try solving on your own before revealing the answer!
Final Answer:
The solution is , or in interval notation.
Q8. Solve the quadratic equation by factoring:
Background
Topic: Quadratic Equations by Factoring
This question tests your ability to solve quadratic equations by factoring.
Key Terms and Formulas
Quadratic equation:
Factoring: Expressing as a product of binomials.
Step-by-Step Guidance
Rewrite the equation in standard form: .
Factor the quadratic expression.
Set each factor equal to zero and solve for .
Try solving on your own before revealing the answer!
Final Answer: or
Factoring gives , so or .
Q9. A person will devote 34 years total to sleeping and watching TV over a lifetime. The years spent sleeping exceed the years spent watching TV by 18. How many years will the person spend on each activity?
Background
Topic: Linear Models and Applications
This question tests your ability to set up and solve a system of equations based on a word problem.
Key Terms and Formulas
Let = years sleeping, = years watching TV.
System: , .
Step-by-Step Guidance
Set up the two equations: and .
Substitute from the second equation into the first.
Solve for , then use that value to find .
Try solving on your own before revealing the answer!
Final Answer: ,
The person will spend 26 years sleeping and 8 years watching TV.
Q10. Solve the compound inequality:
Background
Topic: Compound Inequalities
This question tests your ability to solve and express compound inequalities in interval notation.
Key Terms and Formulas
Compound inequality: An inequality involving more than one comparison.
Combine like terms and isolate .
Step-by-Step Guidance
Combine like terms: , so .
Add 6 to both sides to isolate .
Divide both sides by 2 to solve for .
Express the solution in interval notation.
Try solving on your own before revealing the answer!
Final Answer:
The solution is , or in interval notation.
Q11. Solve using the quadratic formula:
Background
Topic: Quadratic Formula
This question tests your ability to solve quadratic equations using the quadratic formula.
Key Terms and Formulas
Quadratic formula:
Standard form:
Step-by-Step Guidance
Rewrite the equation in standard form: .
Identify , , .
Plug these values into the quadratic formula.
Simplify under the square root and solve for .
Try solving on your own before revealing the answer!
Final Answer:
Using the quadratic formula, the solutions are and .