Question

How do you find the product of `(-9x^2-10y)^2`?

Answer 1

`(-9x^2-10y)^2=color(blue)(81x^4+180x^2y+100y^2)`

Explanation:

In general `(a+b)^2=a^2+2ab+b^2`

If `a=-9x^2` and `b=-10y`
then
`color(white)("XXX")a^2color(white)("XXX")=81x^4`
`color(white)("XXX")2abcolor(white)("XX")=180x^2y`
`color(white)("XXX")b^2color(white)("XXX")=underline(100y^2)`
`color(white)("XXXXXXXXXX")81x^4+180x^2y+100y^2`