How do you know, whether it is possible to factorise a Quadratic expression?

Question

anonymous · Answer

To be able to factorise a quadratic expression mean it have roots. So the answer u are looking for is the discriminant. 

In the quadratic equation formula:

For a standard ax^2 +bx+c = 0 eqn, 
the formula to solve it is

$$x=\frac{ -b \pm \sqrt{b ^{2}-4ac}}{2a}$$

The $$\sqrt{b ^{2}-4ac}$$ portion is called the discriminant.

If this discriminant is less than 0, there are no real roots, impossible to factorise without the use of complex numbers (ignore this if u havent learnt it)

If the discriminant is more than 1, mean 2 distinct roots, if 0, it means only 1 root.