Question

tính (2x+3)^2 + (2x-3)^2 - 2(2x+3)(2x-3)

Answer 1

\(\left(2x+3\right)^2+\left(2x-3\right)^2-2\left(2x+3\right)\left(2x-3\right)\)

\(=\left(2x+3-2x+3\right)^2\)

\(=9^2\)

\(=81\)

Answer 2

\(\left(2x+3\right)^2+\left(2x-3\right)^2-2\left(2x+3\right)\left(2x-3\right)\)

\(=\left(2x+3\right)^2-2\left(2x+3\right)\left(2x-3\right)+\left(2x-3\right)^2\)

\(=\left(2x+3-2x+3\right)^2\)

\(=6^2=36\)