Question

Yvonne is thinking of a number. Fifty, decreased by three times the number, is the same as seven times the number, increased by 80. What is Yvonne's number? 

Answer 1

50 - 3x = 7x + 80
50 = 10x + 80
-30 = 10x
x = -3

Answer 2

(50-3)x=7x+80
50x-3x=7x+80
47x=7x+80
-7x    -7x
40x=80
40x/40=80/40
x=2