Question

If 81 is added to a number the result is 39 less than three times the number

Answer 1

60

Explanation:

number is represented as x.

81 is added to a number is

81 + x

39 less than three times the number

3x - 39

So

81 + x = 3x - 39

Solve for x.

81 + x = 3x - 39 Add 39 to each side so 39 cancels on the right.

81 + x + 39 = 3x - 39 + 39

81 + x + 39 = 3x

81 + 39 + x = 3x

120 + x = 3x Subtract x from each side.

120 + x - x = 3x - x

120 = 3x - x

120 = 2x Divide each side by 2

120/2 = 2x/2

120/2 = x

60 = x

Answer 2

let x =the number

Explanation:

81+x=3x-39

group like terms

81+39=3x-x

120=2x

120/2=2x/2

60=x

therefore x =60