Question

How do you multiply `(3x+9)^2`?

Answer 1

I found: `9x^2+54x+81`

Explanation:

Your square can be "translated" as:
`(3x+9)^2=(3x+9)(3x+9)=`
multiplying we get:
`=(3x*3x)+(3x*9)+(9*3x)+(9*9)=`
`=9x^2+27x+27x+81=`
and finally:
`=9x^2+54x+81`