1) (4-x)(4+x)= 16+4x-4x+x^2= 16+x^2 -верно
2) (2x-5)(x-4)= 2x^2 -8x -5x+20=2x^2 - 13x+20
-(5-2x)(4-x)= -(20-5x-8x-2x^2)= -20+13+2x^2 - не верно
3)(x+1)(3-2x)= 3x-2x^2+3-2x= -2x^2+x+3 - верно
4)(x -4)^2= (x -4)(x -4)=x^2-4x-4x+16=x^2-8x+16 - верно
7x - (x + 3) = 3(2x - 1)
7x - x - 3 = 6x - 3
7x - x -6x = 3 - 3
0 = 0
Уравнение верно.
<span>3х-5(2х-1)=3(3-2х)
3х-10х+5=9-6х
3х-10х+5-9+6х=0
-х-4=0
х=-4</span>