CAIE IGCSE Additional Math 5 simultaneous equations

x+2 y=1

B1

Correctly eliminates one unknown

M1

Dep on B1 allow unsimplified e.g.
$$x=1-2 y \text { or } y=\frac{1-x^{2}}{4 x+1}$$

Correct quadratic in solvable form:
$y-4 y^{2}[=0]$ oe or
$2 x^{2}-3 x+1[=0]$ oe

A1

Factorises or solves their quadratic to get two
solutions

M1

Dep on previous M1

y=0, x=1 and $y=\frac{1}{4}, x=\frac{1}{2}$

A1