Mathematics · Grades 9–11
Evaluate a quadratic
Square the input before multiplying by its coefficient.
The key idea
Square the input before multiplying by its coefficient.
f(x) = ax² + bx + c
Worked examples
Find f(-5) if f(x) = 6x² + 1x + 7.
6 × (-5)² + 1 × (-5) + 7 = 152
152
Find f(7) if f(x) = 2x² + 9x + 1.
2 × (7)² + 9 × (7) + 1 = 162
162
Try it yourself
Find f(2) if f(x) = 4x² + 9x + 8.
Find f(-5) if f(x) = 4x² + 5x + 14.
Check your understanding
Answers and marking notes
- 42
4 × (2)² + 9 × (2) + 8 = 42
- 89
4 × (-5)² + 5 × (-5) + 14 = 89
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Learning preview · teacher review required. Grade bands are approximate, not official curriculum alignment.