How to know if equation can be solved by factorising before trying? So, I have core 1 test tomorrow and there is a lot of solving of quadratic equations without calculator and my weakest point is the time I waste in trying to factorise and equation but then it ends up it doesn't factorise or the opposite way in which I use equation while I could've done factorising. Is there any way you can know if equation factorise or not?

You can only factorise easily (without involving surds) if the discriminant is a perfect square. Mind you ,if you've already worked the discriminant out, you may as well go on and solve using the formula.
