Factorize completely the difference of two squares: 9x^2 - 25y^2.
Answer and explanation
Correct answer: B. (3x - 5y)(3x + 5y)
- Step 1: The formula for the difference of two squares is a^2 - b^2 = (a - b)(a + b). Step 2. Here 9x^2 = (3x)^2 and 25y^2 = (5y)^2, so the factorization is (3x - 5y)(3x + 5y). Answer: (3x - 5y)(3x + 5y). Why not the others: (3x - 5y)^2 expands to 9x^2 - 30xy + 25y^2; (3x + 5y)^2 expands with +30xy; (9x - 25y)(x + y) is not equivalent.
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