Answer:
(3x + 4y - 3z)(3x + 4y + 3z)
Step-by-step explanation:
(3x + 4y)² - (3z)² ← is a difference of squares and factors in general as
a² - b² = (a - b)(a + b)
Here a = 3x + 4y and b = 3z, then
(3x + 4y)² - (3z)²
= (3x + 4y - 3z)(3x + 4y + 3z) ← in factored form
