Answer:
20(2p - 3r)(2p + 3r)
Step-by-step explanation:
Given
80p² - 180r² ← factor out 20 from each term
= 20(4p² - 9r²) ← difference of squares which factors in general as
a² - b² = (a - b)(a + b)
4p² - 9r²
= (2p)² - (3r)² ← with a = 2p and b = 3r
= (2p - 3r)(2p + 3r)
Thus
80p² - 180r² = 20(2p - 3r)(2p + 3r) ← in factored form
