Đáp án:
Giải thích các bước giải:
`(\frac{a}{2}-4)^2`
`=(\frac{a}{2})^2-2.\frac{a}{2}.4+4^2`
`=\frac{a^2}{4}-4a+16`
`(\frac{a}{3}+4y)^2`
`=(\frac{a}{3})^2+2.\frac{a}{3}.4y+(4y)^2`
`=\frac{a^2}{9}+\frac{8}{3}ay+16y^2`
`(\frac{1}{x}-3y)^2`
`=(\frac{1}{x})^2-2.\frac{1}{x}.3y+(3y)^2`
`=\frac{1}{x^2}+\frac{6y}{x}+9y^2`
`(\frac{x}{2}-\frac{yz}{6})(\frac{x}{2}-\frac{yz}{6})`
`=(\frac{x}{2})^2-(\frac{yz}{6})^2`
`=\frac{x^2}{4}-\frac{y^2z^2}{36}`
`(x^2+\frac{2}{5}y)(x^2-\frac{2}{5}y)`
`=(x^2)^2-(\frac{2}{5}y)^2`
`=x^4-\frac{4}{25}y^2`