Advanced MathHardQuadratic with no x term from two values
Advanced Math practice question
The function f is defined by f(x) = ax² + c, where a and c are constants. If f(0) = 3 and f(2) = 11, what is the value of f(3)?
Answer: 21
f(0) = c = 3. Then f(2) = 4a + 3 = 11, so a = 2. f(3) = 2(9) + 3 = 21.
Common wrong answers
- If you answered 15
- 15 is f(3) with a = 4/3 or a similar slip; f(2) = 11 gives 4a = 8, a = 2.
- If you answered 18
- 18 is 2 × 9 without adding c = 3.
- If you answered 27
- 27 is 3 × 9, using c as the coefficient of x².
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