(1)4x(a+b)-3x²(a+b);

(1)4x(a+b)-3x²(a+b);
=x(a+b)(4-3x)
(2)a(x-2y)-b(2y-x)-c(x-2y);
=a(x-2y)+b(x-2y)-c(x-2y);
=(a+b-c)(x-2y)
(3)15a²(x-y)-5a(y-x);
=15a²(x-y)+5a(x-y)
=5a(x-y)(3a+1)
(4)(3x+y)(3x-y)-(x+3y)(y-3x);
=(3x+y)(3x-y)+(x+3y)(3x-y)
=(3x+y+x+3y)(3x-y)
=(4x+4y)(3x-y)
=4(x+y)(3x-y)

1.
4x(a+b) - 3x^2(a+b) = x(a+b)(4-3x)
2.
a(x-2y) - b(2y-x) - c(x - 2y) = (x - 2y)(a + b - c)
3.
15a^2(x - y) - 5a(y-x) = 5a(x - y)(3a + 1)
4.
(3x + y)(3x - y) - (x + 3y)(y - 3x) = (3x - y)(3x + y + x + 3y)
= 4(3x - y)(x + y)

(1)4x(a+b)-3x²(a+b) =x(a+b) (4-3x)
(2)a(x-2y)-b(2y-x)-c(x-2y)=(x-2y)(a+b-c)
(3)15a²(x-y)-5a(y-x)=(x-y)(15a²-5a)=5a(x-y)(3a-1)
(4)(3x+y)(3x-y)-(x+3y)(y-3x)=(3x+y)(3x-y)+(x+3y)(3x-y)=(3x-y)(3x+y+x+3y)=4(3x-y)(x+y)