Question

12. Select the values of x that make the

Answer 1

To find out which values of x makes the inequality true, you can either plug in the values into the inequality or solve the inequality to determine what values "x" can be:

Solve the inequality:

To solve the inequality, you need to isolate/get the variable "x" by itself in the inequality

-3(x + 1) > 15    Divide -3 on both sides

$\frac{-3(x+1)}{-3} >\frac{15}{-3}$   When you multiply/divide by a negative number in an inequality, you have to flip the sign (</>)

x + 1 < -5      Subtract 1 on both sides to get "x" by itself

x < -6      [x is any value less than -6]      

This means that x can't be -6 or a number above -6, so the values of x that make the inequality true = -9, -8, and -7

Plug the values in:

x = -9

-3(x + 1) > 15      Substitute/plug in -9 into "x" since x = -9

-3(-9 + 1) > 15

-3(-8) > 15     [two negative signs cancel each other out and become positive]

24 > 15    This is true because 24 is greater than 15

x = -8

-3(x + 1) > 15     Plug in -8 into "x"

21 > 15     This is true because 21 is greater than 15

x = -7

-3(x + 1) > 15     Plug in -7 into "x"

18 > 15      This is true because 18 is greater than 15

x = -6

15 > 15        This is false because 15 is not greater than itself

x = -5

12 > 15      This is false because 12 is not greater than 15

x = -4

9 > 15       This is false because 9 is not greater than 15