Polynomial Factoring Methods Flashcards
7 cards from real IBEW practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Polynomial Factoring Methods flashcards as text
Factor the sum of cubes: 8x³ + 27
Answer: (2x + 3)(4x² - 6x + 9)
Using a³ + b³ = (a + b)(a² − ab + b²) with a = 2x and b = 3: (2x + 3)(4x² − 6x + 9).
Which polynomial CANNOT be factored over integers?
Answer: x² + 9
x² + 9 is a sum of squares, which cannot be factored over the integers.
Factor by grouping: 2ax + 2ay + bx + by
Answer: (2a + b)(x + y)
Group as (2ax + 2ay) + (bx + by) = 2a(x + y) + b(x + y) = (2a + b)(x + y).
What value of c makes x² + 8x + c a perfect square trinomial?
Answer: 16
For a perfect square, c = (8/2)² = 4² = 16, giving (x + 4)².
Factor completely: 5x³ - 45x
Answer: 5x(x - 3)(x + 3)
Factor out 5x to get 5x(x² − 9), then factor the difference of squares: 5x(x − 3)(x + 3).
Factor: 9x² - 30x + 25
Answer: (3x - 5)²
9x² − 30x + 25 = (3x)² − 2(3x)(5) + 5² = (3x − 5)², a perfect square trinomial.
Factor: x² - 14x + 49
Answer: (x - 7)²
x² − 14x + 49 = (x − 7)² since 7² = 49 and 2(7) = 14.