Question

What value of x is in the solution set of 9(2x + 1) < 9x – 18?

Answer 1

18x + 9 < 9x - 18
9x < -27
x < 3

Answer 2

Simplify the left side:

18x + 9 < 9x -18

Subtract the 9x from both sides:

18x +19 < 9x - 18
-9x          -9x

9x + 19 < -18

Subtract 19 from both sides:

9x + 19 < -18
       -19    -19

9x < -27

Divide each side by 9:

x = -3