## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$15y^2 - 27y + 30$
We simplify by removing the parentheses and then combine the like terms as follows $$9(y^2 - 3y + 4) - 6(1 - y^2)=9y^2 - 27y + 36 - 6 +6y^2\\ = 15y^2 - 27y + 30 .$$