Factorise: y = x^2 + 5x + 6
With quadratic equations, there are two ways in which to answer
Firstly (and most simply), look for two numbers that multiply to make c and add up to make b in the equation y = ax2 + bx + c , so in the example question, two numbers that add to make 5 and multiply to make 6 are +3 and +2. Therefore, to factorise, insert these numbers along with an x in two different brackets:(x+3)(x+2).
Second method: -b +/- square root (b2-4ac) /2a. This gives 2 solutions to the equation (which are +3 and +2 in this case, as shown in the first example), hence we can factorise accordingly.
Second method should only be used if you're struggling to find solutions using the first method (either due to the equation being difficult, or the solutions not being whole numbers)
