📝 Solve inequalities using the Addition Property of Inequality (12 MCQs)
📖 From Digital SAT Algebra • 2. Linear Equations And Inequalities • 12 questions available
What is Solve inequalities using the Addition Property of Inequality?
Definition:
The Addition Property of Inequality states that adding the same number to both sides of an inequality maintains the inequality direction. If , then . This is used to eliminate subtracted constants.
Working:
For , add 3 to both sides: , giving . The direction remains the same.
Example:
Solve . Add 2: . The solution includes all numbers greater than or equal to -4.
Reason:
This property works identically to its equality counterpart, making it intuitive for students who have learned solving equations.
📝 All Solve inequalities using the Addition Property of Inequality MCQs
Q1. Which inequality is equivalent to after using the Addition Property of Inequality correctly?
📖 Explanation: Adding 7 to both sides preserves the direction of the inequality because the same quantity is added to each side. Thus , giving .
Q2. Which value of makes the inequality equivalent to ?
📖 Explanation: To remove the , add 15 to both sides. This produces , so . Therefore, the value being added is 15.
Q3. Consider . A student subtracts 6 from both sides and obtains . What is the best diagnosis of the error?
📖 Explanation: Subtracting 6 from both sides is appropriate because it cancels the positive 6 attached to . The calculation gives , so , not 20.
Q4. Which inequality has the same solution set as ?
📖 Explanation: Subtracting 18 from both sides isolates : . Therefore . The inequality direction stays the same because subtraction is performed equally on both sides.
Q5. A temperature model gives , where represents the temperature in degrees. Which interpretation correctly describes the solution?
📖 Explanation: Adding 12 to both sides gives . Because the inequality includes equality, a temperature of exactly 17° is allowed, as well as every temperature above 17°.
Q6. A savings account is modeled by , where is the amount currently in the account. What must be true about ?
📖 Explanation: The model subtracts 250 from the account amount. Adding 250 to both sides gives , or . Thus the account must contain more than 850 units of currency.
Q7. Two students solve . Student A obtains , while Student B obtains . Which comparison is correct?
📖 Explanation: Adding 24 to both sides cancels the , giving . Student B incorrectly subtracts 24 again, moving farther from isolating the variable rather than canceling its existing term.
Q8. A number-line graph shows an open circle at -3 with shading extending to the right. Which inequality matches the graph?
📖 Explanation: An open circle means the boundary value is excluded, while shading to the right represents values greater than the boundary. Therefore, the graph represents , not .
Q9. A delivery company requires a driver to complete more than 40 deliveries. If the model is , where is the total number of deliveries, which conclusion follows?
📖 Explanation: Adding 12 to both sides gives , so . This agrees with the stated requirement that the driver must complete more than 40 deliveries, showing the algebraic solution has a meaningful interpretation.
Q10. A student transforms into , then says the inequality should become because subtraction was used. What is wrong with the student's final statement?
📖 Explanation: Subtracting 5 from both sides gives , so . The inequality direction remains unchanged. Reversal occurs when multiplying or dividing by a negative number, not when adding or subtracting.
Q11. A project has a maximum time limit represented by . Another project has a requirement . Which pair correctly describes the allowable values?
📖 Explanation: For the first inequality, subtract 18 to obtain . For the second, add 10 to obtain . Both operations preserve the inequality directions, so option B correctly combines the two solution sets.
Q12. An inequality has the form . A student says that the solution is always , regardless of whether is positive or negative. Is the statement valid?
📖 Explanation: The statement is valid because subtracting from both sides isolates , giving . If itself is negative, subtracting a negative number is equivalent to adding its positive opposite, but the inequality direction still does not reverse.