Question

(a+b)^2 = (a-b)^2 + 4ab 

(a-b)^2 = (a+b)^2 - 4ab

Giúp mình tìm vế phải

Answer 1

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

(a-b)^2 = a^2-2ab+b^2

HT

Answer 2

\(\left(a+b\right)^2=\left(a-b\right)^2+4ab\)

Khai triễn vế phải:

\(\left(a-b\right)^2+4ab\)

\(=a^2-2ab+b^2+4ab\)

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

\(=\left(a+b\right)^2\)

\(\Rightarrow\left(a+b\right)^2=\left(a+b\right)^2-4ab\)

Answer 3

\(\left(a-b\right)^2=\left(a+b\right)^2-4ab\)

Khai triễng vế phải:

\(\left(a+b\right)^2-4ab\)

\(=a^2+2ab+b^2-4ab\)

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

\(=\left(a-b\right)^2\)

\(\Rightarrow\left(a-b\right)^2=\left(a+b\right)^2-4ab\)