Question

Решите задачу: 2) (m+8)²- (m-2n)(m+2n) 4) (n+15)²- n(n-19) 6) (6-5m)(5m+6) + (5m-4)²

Answer 1

$2) (m+8)^2-(m-2n)(m+2n)=m^2+16m+64-(m^2-4n^2)= \\ = m^2+16n+64-m^2+4n^2=4n^2+16n+64 \\ 4) (n+15)^2-n(n-19)=n^2+30n+225-n^2+19n=49n+225 \\ 6) (6-5m)(5m+6) + (5m-4)^2=-(5m-6)(5m+6)+(5m-4)^2= \\ =-(25m^2-36)+25m^2-40m+16=-25m^2+36+25m^2-40m+ \\ + 16=-40m+52$