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 (2x + 1)(x² − 3x + 2)?
Answer: 2x³ − 5x² + x + 2
Expand: 2x(x² − 3x + 2) + 1(x² − 3x + 2) = 2x³ − 6x² + 4x + x² − 3x + 2 = 2x³ − 5x² + x + 2.
If 3x² − 27 = 0, which factored form represents the left side?
Answer: 3(x − 3)(x + 3)
3x² − 27 = 3(x² − 9) = 3(x − 3)(x + 3) by difference of squares.
Which of the following is equivalent to x⁻³?
Answer: 1/x³
A negative exponent means taking the reciprocal: x⁻³ = 1/x³.
Which of the following is equivalent to (3x − 2)/5 + (x + 1)/5?
Answer: (4x − 1)/5
Same denominator: (3x − 2 + x + 1)/5 = (4x − 1)/5.
Which expression is equivalent to (x − 4)² − (x + 4)²?
Answer: −16x
(x − 4)² − (x + 4)² = (x² − 8x + 16) − (x² + 8x + 16) = −16x.
Which of the following is equivalent to x^(2/3)?
Answer: ∛x²
x^(2/3) = (x²)^(1/3) = ∛(x²), the cube root of x squared.
Which of the following is equivalent to 4(x + 2)² − 4(x + 2) − 8?
Answer: 4(x + 2)(x + 1)
Let u = x + 2: 4u² − 4u − 8 = 4(u² − u − 2) = 4(u − 2)(u + 1) = 4(x)(x + 3) = 4x(x + 3).