а) (x-1)(x+1) - x(x-2) = 0
x² - 1 - x² + 2x = 0
-1 + 2x = 0
2x = 1
x = 0,5
б) (3x+1)²-9(x+1)(x-1) = 0
9x²+6x+1 - 9(x²-1) = 0
9x²+6x+1-9x²+9 = 0
6x + 10 = 0
6x = -10
x = -10/6 = -1 4/6 = -1 2/3
Объяснение:
а)(2+а)^2, =(2+а)(2+а)=
=4+2а+2а+а^2=
=4+4а+а^2
б) (2х-1)^2=
=(2х-1)(2х-1)=
=(4х^2-2х-2х+1)=
=4х^2-4х+1
