Помогите не могу решить !

int ot a do b (3x^2 + 1) dx = (3*x^3/3 + x) | ot do b = (x^3 + x) | ot a do b = (b^3 - a^3 + b - a) = 126

b^3 - a^3 + b - a = (b - a)*(b^2 + ab + a^2) + (b - a) = (b - a)*(b^2 + ab + a^2 + 1)
(b - a)*(17 + 1) = 126
(b - a)*18 = 126
b - a = 7