1) (a+b)^2-(a-b)(a+b)=a^2+2ab+b^2-(a^2-b^2)=a^2+2ab+b^2-a^2+b^2=2ab+b^2+b^2=2ab+2b^2
2) (x+2)^2=0x^2+4x+4=0
D=4^2-4*1*4=16-16=0
x=-4/(2*1)=-2
1) (a+b)^2-(a-b)(a+b)=a^2+2ab+b^2-(a^2-b^2)=a^2+2ab+b^2-a^2+b^2=2ab+b^2+b^2=2ab+2b^2
2) (x+2)^2=0
x^2+4x+4=0
D=4^2-4*1*4=16-16=0
x=-4/(2*1)=-2