(y+2)^2-2y(y+2) помогите 30x+3(x-5)^2

Question

(y+2)^2-2y(y+2) помогите
30x+3(x-5)^2

Answer 1

1)(y+2)²-2y(y+2)=y²+4y+4-2y²-4y=4-y²=2²-y²=(2+y)(2-y)
   (y+2)²-2y(y+2)=(y+2)(y+2-2y)=(y+2)(2-y)=-(y+2)(y-2)=-(y²-2²)=
   =-(y+2)(y-2)=(2+y)(2-y)
2)30x+3(x-5)²=30x+3(x²-10x+25)=30x+3x²-30x+75=3x²+75=3(x²+25)