Question

How do you factor `3y^2 + 21y + 36`?

Answer 1

`=3(y^2+7y +12)`
`=3(y^2+4y+3y +12)`
`=3(y(y+4)+3(y +4))`
`=3(y+4)(y+3)`

Answer 2

`(3y+9)(y+4)`

Explanation:

Factors of 36 `->` {1 , 36}, {2 , 18}, {3 , 12}, {4, 9}

Factors of 3 `->` {1 , 3}

I have already experimented with these and found that the combination is:

`3(y+3)(y+4)`