Advanced MathMediumLarger zero of a quadratic
Advanced Math practice question
The function f is defined by f(x) = x² − 4x − 12. The function has two zeros. What is the larger zero?
Answer: 6
Factor: x² − 4x − 12 = (x − 6)(x + 2), so the zeros are 6 and −2. The larger is 6.
Common wrong answers
- If you answered 2
- 2 is the x-coordinate of the vertex (halfway between the zeros), not a zero.
- If you answered 12
- 12 is the constant term, not a zero: f(12) = 84.
- If you answered -2
- −2 is the SMALLER zero.
More Advanced Math questions
- Medium
What are the solutions to x² − 5x + 6 = 0? - Medium
The graph of f(x) = (x − 3)² + 4 is a parabola. What are the coordinates of its vertex? - Medium
If x² − 2x − 8 = (x + 2)(x − a), what is the value of a? - Medium
If √(x + 5) = 4, what is the value of x? - Medium
If f(x) = x + 3 and g(x) = 2x, what is f(g(4))? - Medium
What are the solutions to x² + 6x + 8 = 0?
Not affiliated with the College Board. SAT is a trademark of the College Board.