Question

Help tui nha

Answer 1

a: \(\left(3x+2\right)^2=\left(3x\right)^2+2\cdot3x\cdot2+2^2\)

\(=9x^2+12x+4\)

b: \(\left(x-\dfrac{2}{3}\right)^2=x^2-2\cdot x\cdot\dfrac{2}{3}+\left(\dfrac{2}{3}\right)^2\)

\(=x^2-\dfrac{4}{3}x+\dfrac{4}{9}\)

c: \(\dfrac{1}{4}x^2-\dfrac{1}{9}y^2\)

\(=\left(\dfrac{1}{2}x\right)^2-\left(\dfrac{1}{3}y\right)^2\)

\(=\left(\dfrac{1}{2}x-\dfrac{1}{3}y\right)\left(\dfrac{1}{2}x+\dfrac{1}{3}y\right)\)