Mathematics for IGCSE & O level - Algebraic Manipulation (Section 4 - No. 5)
When factoring a quadratic expression of the form x² + bx + c, and if 'c' is negative, what do you know about the signs of the two numbers you are looking for?
Both numbers are positive
Both numbers are negative
The numbers have different signs
The numbers have the same sign
คำอธิบาย
When 'c' is negative, the two numbers that multiply to 'c' will have opposite signs to result in a negative product.