Mathematics Knowledge (MK): practice questions

Correct: B. Distribute: 3x − 12 = 2x + 1. Subtract 2x: x − 12 = 1. Add 12: x = 13.

• D — 5 results from forgetting to distribute the 3 to −4.
• A — 11 results from writing the right side as 2x − 1 instead of 2x + 1.
• C — −13 reverses the sign in the final step.

Correct: C. Power of a power multiplies exponents: (2³)² = 2⁶ = 64. Multiplying by 2⁻² subtracts 2 from the exponent: 2⁴ = 16.

• B — 8 = 2³, missing the square.
• D — 32 = 2⁵.
• A — 64 = 2⁶, ignoring the 2⁻² factor.

Correct: D. Pythagorean theorem: 6² + 8² = 36 + 64 = 100; √100 = 10.

• A — 12 is not √100.
• B — 14 is the sum of the legs, not the hypotenuse.
• C — 48 is the product of the legs.

Correct: A. Subtract 6: −2x > 4. Divide by −2 and flip the inequality: x < −2.

• D — Forgetting to flip the sign gives x > −2.
• B — Sign error on the constant.
• C — Sign error on the constant and direction.

Correct: B. Area πr² = 49π → r = 7. Circumference = 2πr = 14π.

• A — 7π uses r instead of 2r.
• C — 49π is the area, not the circumference.
• D — 98π doubles the area.