Question

Помогите пожалуйста.
x^2+x=20

Answer 1

x^2 + x - 20 = 0 
D = 1 + 4*20 = 81 = 9^2
x1 = ( - 1 + 9)/2 = 8/2 = 4
x2  = ( - 1 - 9)/2 = - 10/2 = - 5