How do I solve a quadratic equation?
All quadratic equations can be written in the form ax2 + bx + c = 0, where a, b and c are constants. Firstly, check whether you can easily factorise the equation into the form (x + p)(x + q) = 0, where pq = c and p + q = b. If you can do this, then the roots of the quadratic equation are -p and -q.
If the equation does not factorise nicely, then the quadratic formula can be used to find the roots of the equation. Again, write the equation in form ax2 + bx + c = 0. Then the quadratic formula is given by x = (-b +/- sqrt(b2 - 4ac))/2a. This will give us two roots to the equation if b2 - 4ac > 0, one root to the equation if b2 - 4ac = 0 and no roots if b2 - 4ac < 0. Use a calculator to find the value of the root(s).
