A quadratic equation has a squared term as its highest power, such as $x^2-x-6=0$. The graph above is of $y=(x+2)(x-3)=x^2-x-6$, so its roots are $x=-2$ and $x=3$. In this lesson, we focus on equations of the form $x^2+bx+c=0$, where the coefficient of $x^2$ is 1.

When we solve a quadratic, we are finding the values of the variable that make the equation true. On a graph, these values are the roots, where the curve crosses the x-axis.

A common GCSE method is factorising, which rewrites the quadratic as a product of two brackets. Then the zero product rule lets us solve each bracket.