Question

срочно даю 50 балов
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Answer 1

Формулы:

a²-b²=(a-b)(a+b)

(a±b)²=a²±2ab+b²

a³-b³=(a-b)(a²+ab+b²)

___________________

4.

(2b-7)²=(2b)²-2•7•2b+7²=4b²-28b+49

(2+5m)(5m-2)=(5m+2)(5m-2)=(5m)²-2²=25m²-4

5.

1)p²+10p+25=p²+10p+5²=(p+5)²

2)-100+0,09c²=(0,3c)²-10²=(0,3c-10)(0,3c+10)

3)d³-64=d³-4³=(d-4)(d²+4d+16)

4)3c²-3d²=3(c²-d²)=3(c-d)(c+d)

6.

(5у+2)²+(9+5у)(9-5у)=

=(25у²+20у+4)+(9²-(5у)²)=

=25у²+20у+4+81-25у²=

=20у+85

при у=3/20 =>

20•3/20 +85=3+85=88

Ответ:88