Упростить1) (а+3)²+(а-3)²2) (4а+b)²-(4a-b)²3) (2-a/b)²-a²/b²4) (1-7b)²-(1+7b)²

Question

Упростить
1) (а+3)²+(а-3)²
2) (4а+b)²-(4a-b)²
3) (2-a/b)²-a²/b²
4) (1-7b)²-(1+7b)²

Answer 1

1) (а+3)²+(а-3)²=
=a²+6a+9+a²-6a+9=
=2a²+18=
=2(a²+9)
2) (4а+b)²-(4a-b)²
=16a²+8ab+b²-16a²+8ab+b²=
=16ab+2b²=
=2b(8a+b)