Twice the sum of a number is 9 is equal to three times the difference of the number and 7

"Twice the sum of a number is 9 is equal to three times the difference of the number and 7" is our problem. Let's translate it into an equation.

Twice                                      2 times

the sum of a number           x +

and 9                                    9

is equal to                              =

three times                           3 times

the difference of a number x-

and 7                                      7

We move top down on the right side and make the equation. Then we solve it for x

2x + 9 = 3x - 7                           our equation

-x + 9 = -7                                    subtract 3x on both sides

-x = -16                                      subtract 16 on both sides

x = 16                                         divide both sides by -1

Thus the mystery number is 16.

true

step-by-step explanation: