Question

Write the following as an algebraic expression. Then simplify.

Five times the sum of some number plus 3 is
equal to 9 times the number minus 9.

Answer 1

Five times the sum of some number plus 3 is equal to 9 times the number minus 9.

5 (x + 3) = 9x - 9

expand left side:

5x + 15 = 9x - 9

subtract 15 from both sides:

5x + 15 - 15 = 9x - 9 - 15

5x = 9x - 24

subtract 9x from both sides:

5x - 9x = 9x - 24 - 9x

-4x = -24

divide both sides by -4:

-4x/(-4) = -24/(-4)

x = 6