Question

How do you factor by grouping `9x^2 + 3xy + 3x + y`?

Answer 1

`9x^2 + 3xy + 3x + y`

We can make groups of two to factorise this expression:
`color(blue)(9x^2 +3x) + color(red)(3xy +y)`

`color(blue)(3x` is common to both the terms in the first group, and `color(red)(y` is common to both the terms in the second group:

We can write the expression as :
`3x(3x +1) + y(3x +1)`

`=color(green)((3x+y)(3x+1)` , is the factorised form.