OAR OAR Math Skills: Algebraic Expressions 3 — Questions and Answers
Question 1: Simplify: (2x + 3)(x - 4)
- 2x² - 5x - 12 (Correct answer)
- 2x² + 5x - 12
- 2x² - 5x + 12
- 2x² - x - 12
Correct answer: 2x² - 5x - 12
FOIL: 2x² - 8x + 3x - 12 = 2x² - 5x - 12.
Question 2: What is the value of 3x² - x + 4 when x = -1?
- 8 (Correct answer)
- 6
- 2
- 0
Correct answer: 8
3(1) - (-1) + 4 = 3 + 1 + 4 = 8.
Question 3: Which expression represents 'six less than twice a number n'?
- 2n - 6 (Correct answer)
- 6 - 2n
- 2n + 6
- 6n - 2
Correct answer: 2n - 6
'Twice a number' is 2n, and 'six less than' means subtract 6, giving 2n - 6.
Question 4: Simplify: 5x - 2(3 - x)
- 7x - 6 (Correct answer)
- 3x - 6
- 7x + 6
- 3x + 6
Correct answer: 7x - 6
Distribute the -2: 5x - 6 + 2x = 7x - 6.
Question 5: Factor completely: x² - 9
- (x+3)(x-3) (Correct answer)
- (x-3)²
- (x+9)(x-1)
- (x-3)(x-3)
Correct answer: (x+3)(x-3)
x² - 9 is a difference of squares: (x+3)(x-3).
Question 6: If 3(x - 2) = 15, what is x?
- 7 (Correct answer)
- 5
- 9
- 3
Correct answer: 7
Divide both sides by 3: x - 2 = 5, so x = 7.
Question 7: Which expression is NOT equivalent to 12x²y?
- 4xy · 4xy (Correct answer)
- 3x · 4xy
- 2x · 6xy
- 12x²y¹
Correct answer: 4xy · 4xy
4xy · 4xy = 16x²y², which does not equal 12x²y.
