What is 3y^2+3 (4y^2-2) ?

It's a 2nd degree algebraic expression in ' y '.

It's pretty messy in this form, and it can be substantially cleaned up.

Looking at just the second term, we can remove the parentheses:

3 (4y² - 2) = 12y² - 6

Now we can put that into the original expression ... 3y² + 12y² - 6

then combine the y² terms: 15y² - 6.

If you want to go one step farther, we can factor it: 3 (5y² - 2)