Quadratic Functions and Equations in One Variable
Coefficient
The number multiplying a variable; in ax² + bx + c the coefficients are a, b and c.
| English | Coefficient |
|---|---|
| Bahasa Melayu | Pekali |
| 中文 | 系数 |
How it is used
In 3x² − 7x + 4, the coefficient of x² is 3, the coefficient of x is −7, and the constant term is 4. So when you use the formula, a = 3, b = −7 and c = 4.
Where it shows up in SPM
A basic idea used across algebra, but critical here for reading a, b, c correctly (Form 4). In Paper 1 sign errors on the coefficient of x are a common trap; in Paper 2 the coefficient a fixes the shape and the discriminant depends on all three.
Don't confuse it with
Open the chapter: Quadratic Functions and Equations in One Variable →
Frequently asked questions
Is the coefficient of x in x² − 7x equal to 7 or −7?
It is −7. The coefficient always includes the sign in front of the term, so the minus belongs to it.
Getting this wrong flips the sign of b and gives the wrong discriminant and wrong roots.
If there is just x², what is its coefficient?
The coefficient is 1, because x² means 1 × x². Similarly a lone x has coefficient 1.
Writing the invisible 1 explicitly helps when substituting into the quadratic formula.