Question

Khai triển hằng đẳng thức sau:

(3x²+\(\dfrac{2}{3}\)y)²

Answer 1

\(\left(3x^2+\dfrac{2}{3}y\right)^2\)

\(=\left(3x^2\right)^2+2.3x.\dfrac{2}{3}y+\left(\dfrac{2}{3}y\right)^2\)

\(=9x^4+4xy+\dfrac{4}{9}y^2\)

Answer 2

(3x²+\(\dfrac{2}{3}\)y)²

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