Algebra 9

2 marks · Normal

Solve the simultaneous equations for :

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x = 3\text{ or }x = -1

Also accept: x = 3 and x = -1

Common mistakes: Only finding one solution, e.g. x=3

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Marking points

M1 · 1 mark · Substitutes the linear equation into the quadratic to form and solve x² = 2x + 3 (or equivalent substitution).

A1 · 1 mark · Both correct solutions: x = 3 and x = -1.

Worked solution

Substitute y from the first equation into the second:

Rearrange:

Factorise:

So x = 3 or x = -1.