Answer:
6p + 51
Step-by-step explanation:
Given
(p + 10)² - (p + 7)² ← expand both parenthesis using FOIL
= p² + 20p + 100 - (p² + 14p + 49) ← distribute by - 1
= p² + 20p + 100 - p² - 14p - 49 ← collect like terms
= 6p + 51