Question

Решить систему

 

x-y=1

x^3-y^3=7

Answer 1

x=1+y
(1+y)*(1+y)*(1+y)-y*y*y=7
1 + 3y + 3y*y + y*y*y - y*y*y=7
1+3y+3y-y=7
y=1
y= -2

Answer 2

$left { {{x-y=1} atop {x^3-y^3=7}} right. \ x=y+1 \ (y+1)^3-y^3=7 \ y^3+3y^2+3y+1-y^3=7 \ y^2+y-2=0 \ D=1+8=9 \ y_1= frac{-1-3}{2}=-2 \ y_2= frac{-1+3}{2}=1 \ x_1=y_1+1=-2+1=-1 \ x_2=y_2+1=1+1=2$
Ответ: (-1; -2); (2; 1)