(5x^2 +4x -1)/(x^2 -1) = 6|·(x^2 -1) ≠ 0
x^2 ≠ 1
x ≠ +-1
5x^2 +4x -1 = 6( x^2 -1)
5x^2 + 4x -1 = 6x^2 -6
5x^2 +4x - 1 - 6x^2 +6 = 0
-x^2 +4x +5 =0 |·(-1)
x^2 -4x -5 =0
x = 5 x = -1 (посторонний корень)
Ответ х = 5
2x+y=7 = x=2-y
/x-y/=2 = 2 (2+y)+y=7
2 (2-y)+y=7
4-2y+y=7
-y=7-4
-y=3
y=3
x=2-(-3)=-5