How do I find roots of a quadratic equation when I can't factorise?

When factorising isn't working, we can try using the quadratic formula. First, we need our quadratic equation and find a,b and c - the coefficients of x and the constant. Now, we can write out the quadratic formula and plug in the corresponding numbers. Remember there are two different answers given by this method. With a calculator this is nice and easy - just type it in and write the answer to 2/3 decimal places (if needed). Without a calculator we can just simplify as far as possible so we might still have a surd in the answer but that's OK.