Question

Найдите корни уравнения х2-7х =8

Answer 1

x^2 - 7x - 8 = 0 
D = 49 + 4*8 = 81 = 9^2
x1 = ( 7 + 9)/2 = 16/2 = 8;
x2 = ( 7 - 9)/2 = - 2/2 = - 1;

Answer 2

$x^2-7x-8=0, D=49+32=81=9^2 \\ x_1= \frac{7+9}{2} =8 \\ x_2= \frac{7-9}{2} =-1$
Ответ: х=-1, х=8.