How to solve
Look for p and q with p·q = c and p + q = b; then x² + bx + c = (x + p)(x + q).
Steps
- List factor pairs of the constant c.
- Pick the pair adding to b (watch signs).
- Write the two binomial factors.
Example
Factor x² + 2x − 15.
- Need p·q = −15, p + q = 2.
- 5 and −3 work.
Answer: (x+5)(x-3)
Loading drills…