As a graph cuts the axis when the y coordinate is zero, then we substitute \(y = 0\) into the quadratic equation and use algebra to solve. We need to factorise the trinomial. When factorised this ...

Looking at the graph we can see that the roots occur at (-1, 0) and (3, 0), therefore \(x = - 1\) and \(x = 3\). Now try the example question below. Solve the quadratic equation \({x^2} ...