Let one number be x. Given, sum = 18
∴ Other number = (18 – x)
∴ x(18 - x) - 56 ⇒ 18x - x2 = 56 ⇒ x2 - 18x + 56 = 0
x - 14x -4x + 56 = 0
⇒ x(x - 14) -4(x - 14) = 0
⇒ (x - 4)(x - 14) = 0 ⇒ (x - 4) = 0 or (x - 14) = 0 ⇒ x = 4, 14
∴ The numbers are 4 and 14.