Памогите срочно пж пж пж#4и#5#6

Question

Памогите срочно пж пж пж#4и#5#6

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Answer 1

4. a^2+2ab+b^2-2ab+a^2-b^2=
a*2a, 2a^2=a*2a, a*2a=a*2a

5. x^2(x+2)-4(x+2)=0
(x+2)(x^2-4)=0, x+2=0, x1= -2
x^2-4=0, (x-2)(x+2)=0,
x-2=0, x2=2, x3=-2