Answer:
cos²A - cosA - 6
Explanation:
Given
(cosA + 2)(cosA - 3)
Each term in the second factor is multiplied by each term in the first factor, that is
cosA(cosA - 3) + 2(cosA - 3) ← distribute both parenthesis
= cos²A - 3cosA + 2cosA - 6 ← collect like terms
= cos²A - cosA - 6