Question

rút gọn: ( 4x + 5 ) ² - 2 ( 4x + 5 ) ( x + 5 ) + ( x + 5 )²

Answer 1

Có: \(\left(4x+5\right)^2\) + 2(4x + 5)(x + 5) + \(\left(x+5\right)^2\)

= \(\left(4x+5+x+5\right)^2\)

= \(\left(5x+10\right)^2\)

Answer 2

\(\left(4x+5\right)^2-2\left(4x+5\right)\left(x+5\right)+\left(x+5\right)^2\)

\(\Leftrightarrow\left[\left(4x+5\right)-\left(x+5\right)\right]^2\)

\(\Leftrightarrow\left(4x+5-x-5\right)^2\)

\(\Leftrightarrow3x^2\)