Final answer:
To perform the indicated operations, simplify the expressions inside the parentheses and then substitute them back into the main expression.
Step-by-step explanation:
To perform the indicated operations, we need to simplify the expression step by step.
First, let's simplify the expression inside the first set of parentheses:
(9y² + 6y + 3) - (-7y² + 2y - 5) = 9y² + 6y + 3 + 7y² - 2y + 5 = (9y² + 7y²) + (6y - 2y) + (3 + 5) = 16y² + 4y + 8.
Next, let's simplify the expression inside the second set of parentheses:
(5y² - 3y - 4) + (10y² + 9y + 2) = 5y² - 3y - 4 + 10y² + 9y + 2 = (5y² + 10y²) + (-3y + 9y) + (-4 + 2) = 15y² + 6y - 2.
Finally, let's substitute the simplified expressions back into the main expression:
(16y² + 4y + 8) - (15y² + 6y - 2) = 16y² + 4y + 8 - 15y² - 6y + 2 = (16y² - 15y²) + (4y - 6y) + (8 + 2) = y² - 2y + 10.