<span>(x+1)²+(x-1)²=x²+2x+1+x²-2x+1=2x²+2=2·(x²+1)</span>
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1) (m+3)2
2) (4+7z)2
3) 4(25d2 + 1 +10d)=4(5d+1)2
4)(c-2)2
5) (7-6y)2
6) 25(a2+4ad+4d2)=25(a+2d)2
7)(2m-7)2
8)(9-2z)2
9) (6d-1)2
10) (a-2)2
B4+b7=b1q³ +b1q^6=b1q³(1+q³)=b1q³(1+q)(1-q+q²)=756
b5-b6+b7=b1q^4-b1q^5+b1q^6=b1q^4(1-q+q²)=567⇒b1q³(1-q+q²)=567/q
(1+q)*567/q=756 q≠0
756q-567q=567
189q=567
q=3
b1=756/q³(1+q³)=756/27*28=1
1ст- x; 2 ст- x-3; 3ст- x+5; x+x+5+x-3=41;3x=39;x=13;2ст=10;3ст=18; 18/10=1,8; Ответ в 1,8 раза