Решите пожалуйста !!!!!!!!!!!!!!!!!!!!!!!!!!!!!
1 карточка
1.2cd+c^2+d^2=c^2+2cd+d^2=(c+d)^2
2.4-4x+x^2=2^2-2*2*x+x^2=(2-x)^2
3.64+16b+b^2=8^2+2*8*b*b^2=(8+b)^2
4.x^2-14x+49=x^2-2*x*7+7^2=(x-7)^2
5.a^2+81-18a=a^2-18+81=(a-9)^2
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