Equivalent Expressions Flashcards
7 cards from real Bluebook SAT Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Equivalent Expressions flashcards as text
Which of the following is equivalent to (3x + 1)/(9x² − 1)?
Answer: 1/(3x − 1)
Factor denominator: 9x²−1 = (3x+1)(3x−1); cancel (3x+1) to get 1/(3x−1).
Which expression is equivalent to (a + b + c)² − a² − b² − c²?
Answer: All of the above except C
Expanding (a+b+c)² = a²+b²+c²+2ab+2ac+2bc; subtracting a²+b²+c² leaves 2ab+2ac+2bc = 2(ab+ac+bc).
Which of the following is equivalent to (x − 3)(x + 3) + 2(x + 3)?
Answer: (x + 3)(x − 1)
Factor out (x+3): (x+3)[(x−3)+2] = (x+3)(x−1).
Which of the following is equivalent to (√x + √y)(√x − √y)?
Answer: x − y
Difference of squares: (√x)²−(√y)² = x−y.
Which of the following is equivalent to 4x(x + 2) − (x + 2)²?
Answer: (x + 2)(3x − 2)
Factor (x+2): (x+2)[4x−(x+2)] = (x+2)(4x−x−2) = (x+2)(3x−2).
Which expression is equivalent to x² − 4x + 4 − 9y²?
Answer: (x − 2 − 3y)(x − 2 + 3y)
Group as (x−2)²−(3y)²; apply difference of squares: (x−2−3y)(x−2+3y).
Which of the following is equivalent to (x⁴ − 1) / (x² + 1)?
Answer: x² − 1
Factor numerator: x⁴−1 = (x²+1)(x²−1); divide by (x²+1) to get x²−1.