Question

VA ROG AJUTOR!!!Sa se arate ca pt oricare a,b∈R avem:
a) (a+b)²=a²=2ab+b²

Answer 1

(a+b)²=(a+b)(a+b)=$a^{2}$+ab+ab+$b^{2}$
$a^{2}$+2ab+$b^{2}$

Answer 2

$(a+b)^2=(a+b)(a+b)=a(a+b)+b(a+b)=a^2+ab+ab+b^2= \\ =a^2+2ab+b^2$