To find the value of (x+6)(x+6) = 256, you first need to simplify the left hand side of the equation: (x+6)(x+6) = x2 +6x +6x + 36 = x2 + 12x + 36 Substituting this to the original equation will give you this x2 + 12x + 36 = 256, which can further be simplified by moving all terms to the left. Doing that will give you the quadratic form (ax2 + b2 + c = 0) of the equation: x2 + 12x - 220 = 0 Remember that the roots can be obtained by using the quadratic formula given by: x = [(-b)±√b2-(4ac)] / 2a where a, b, c are the coefficients of the equation. That is, a = 1, b = 12 and c = -220 Substituting the values will give you: x = [-(12)±√(12)2-(4*1*-220)] / 2(1) x = [-12±√144-(-880)] / 2 x = [-12±√1024] / 2 x = [-12±32] / 2 First root now equals to: x = [-12+32] / 2 x = 10 Second root: x = [-12-32] / 2 x = -22 There you have it. The values of x are 10 and -22.