Question

If thrice of a number is diminished by 7,the result is 9 more than the number.........find the number !

Answer 1

assume the number as x

according to the question

          3x - 7 = x + 9

          3x = x + 9 +7

          3x = x +16

          3x - x = 16

          2x = 16

          x = 16 / 2

          x = 8

therefore the number is 8

substution

     3(8) - 7 = 8 +9

     24 - 7 = 17

     17 = 17

     LHS = RHS