Question

What is the standard form of `y=x^2(x+4)(x-5) -x^2`?

Answer 1

`y=x^2(x^2-x-21)`
or
`y=x^4-x^3-21x^2`

Explanation:

`y=x^2(x+4)(x-5)-x^2=`

`=x^2[(x+4)(x-5)-1]=`

`=x^2[x^2-x-20-1]=`

`=x^2[x^2-x-21]=`

`=x^4-x^3-21x^2`