Question

Check all polynomials that are perfect square trinomials:
Answer







4a2 - 20a + 25








25b^2 - 5b + 10








16x2 - 8x + 1








49x^2 - 8x + 16

Answer 1

4a² − 20a + 25 = (2a – 5)²
16x² − 8x + 1 = (4x – 1)²
If ax² + bx + c is a perfect square, then the discriminant is 0. The discriminant = b² - 4ac
49x² − 8x + 16: discriminant = (-8)² - 4(49)(16) = -3072
4a² − 20a + 25: discriminant = (-20)² - 4(4)(25) = 0
25b² − 5b + 10: discriminant = (-5)² - 4(25)(10) = -975
16x² − 8x + 1: discriminant = (-8)² - 4(16)(1) = 0

Answer 2

first and third.