Mathematics for IGCSE & O level - Algebraic Manipulation (Section 4 - No. 13)
For the expression x² + 4x - 21, after identifying factors, what will be the signs of the numbers?
Both are positive
Both are negative
One is positive and one is negative
Cannot be determined
Explication
Because the constant term is negative, the two factors must have opposite signs to multiply to a negative product.