Answer:
P - Q = - 11b² + 8b - 4
Step-by-step explanation:
P - Q
= - 4b² + 6b - 9 - (7b² - 2b - 5) ← distribute parenthesis by - 1
= - 4b² + 6b - 9 - 7b² + 2b + 5 ← collect like terms
= - 11b² + 8b - 4
