Mathematics for IGCSE & O level - Algebraic Manipulation (Section 3 - No. 17)
When factoring quadratic expressions of the form x² + bx + c where 'c' is positive, what can be inferred about the signs of the factors?
The factors have different signs.
The factors have the same sign.
Only one factor is positive.
The factors are always positive.
Giải thích
If 'c' is positive, both factors have the same sign: either both positive or both negative.