| Exam Board | OCR MEI |
|---|---|
| Module | C3 (Core Mathematics 3) |
| Marks | 4 |
| Paper | Download PDF ↗ |
| Mark scheme | Download PDF ↗ |
| Topic | Modulus function |
| Type | Solve k|linear| compared to |linear| |
| Difficulty | Standard +0.3 This is a straightforward modulus equation requiring consideration of cases based on sign changes. Students need to identify critical points (x=0 and x=3/2), test regions, and solve resulting linear equations. While it requires systematic case analysis, the algebra is simple and the technique is standard for C3, making it slightly easier than average. |
| Spec | 1.02l Modulus function: notation, relations, equations and inequalities1.02t Solve modulus equations: graphically with modulus function |
# Question 1
M1: $3 - 2x = 4x$ or $3 - 2x = -4x$
A1: $x = \frac{1}{2}$ or $x = -\frac{3}{2}$
or
M1: $(3 - 2x)^2 = 16x^2$ (squaring both sides)
M1: $12x^2 + 12x - 9 = 0$ (correct quadratic o.e. but with single $x^2$ term)
A1: $x = \frac{1}{2}$
A1: $x = -\frac{3}{2}$
**Guidance notes:**
Not $\frac{3}{-2}$
If 3 or more final answers offered, $-1$ for each incorrect additional answer
$-1$ for final answer written as an inequality
$(3 - 2x)^2 = 4x^2$ is M01 Solve the equation $| 3 - 2 x | = 4 | x |$.
\hfill \mbox{\textit{OCR MEI C3 Q1 [4]}}