giúp e vs ạ
a: \(\left(\dfrac{3}{2}x+2y\right)^2\)
\(=\left(\dfrac{3}{2}x\right)^2+2\cdot\dfrac{3}{2}x\cdot2y+\left(2y\right)^2\)
\(=\dfrac{9}{4}x^2+6xy+4y^2\)
b: \(\dfrac{1}{8}x^3-8y^3\)
\(=\left(\dfrac{1}{2}x\right)^3-\left(2y\right)^3\)
\(=\left(\dfrac{1}{2}x-2y\right)\left[\left(\dfrac{1}{2}x\right)^2+\dfrac{1}{2}x\cdot2y+\left(2y\right)^2\right]\)
\(=\left(\dfrac{1}{2}x-2y\right)\left(\dfrac{1}{4}x^2+xy+4y^2\right)\)
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