NECO 2023 · Paper 1 · Q23

Use the graph (a quadratic graph and a straight line) to answer: find the equation of the quadratic graph (the equation whose roots it shows).

The vertical scale is half the horizontal scale.

Worked solution (try it first)

The curve cuts the $x$ -axis at $x = -1$ and $x = 2$ , so the factors are $(x + 1)$ and $(x - 2)$ .
Expand: $(x + 1)(x - 2) = x^2 - 2x + x - 2$
$= x^2 - x - 2$ .
So the equation is $x^2 - x - 2 = 0$ , option A.