SOLUTION: When an unknown number is decreased by 15, the result is twice the opposite of that number. Find the mystery number.

Algebra ->  Customizable Word Problem Solvers  -> Numbers -> SOLUTION: When an unknown number is decreased by 15, the result is twice the opposite of that number. Find the mystery number.       Log On

    x - 15 = 2*(-x)


    x - 15 = -2x


    x + 2x = 15


      3x   = 15


       x   = 15/3 = 5.     ANSWER