Let N be the original number
So......
2N + 28 = (4/9)N subtract (4/9)N and 28 from both sides
2N - (4/9)N = -28 get a common denominator on the left
(18/9)N - (4/9)N = -28
(14/9)N = - 28 multiply both sides by 9/14
N = -28 (9/14) = -2 * 9 = -18 is the original number
