a)4(m-n)²+4m(m-n) = (m-n)(4m-4n+4m)=(m-n)(8m-4n)=4(m-n)(2m-n)
b)5x(x-y)-2(y-x)²= (y-x)(-5x-2y+2x)=(y-x)(-2y-3x)=(x-y)(2y+3x)
v)(y+7)²-2(y+10)(y+4)= y²+14y+49-2(y²+14y+40)= y²+14y+49-2y²-24y-80 = -y²-14y-31
g)(x-5) (6+4x)-3(1-x)²= 6x+4x²-30-20x-3(1-2x+x²)= 4x²-14x-30-3+6x-3x²= x² -8x-33