a) 2x2+4xy =2x(x+2y)
b) 10x(x-y)+6y(x-y)=(10x+6y)(x-y)=2(5x+3y)(x-y)
a) 2x2 + 4xy = 2x(x + 2y)
b) 10x(x - y) + 6y(x - y)
= (x - y)(10x + 6y)
= 2(x - y)(5x + 3y)
c) x2 - 25 - 2xy + y2
= (x2 - 2xy + y2) - 25
= (x - y)2 - 52
= (x - y - 5)(x - y + 5)