How do I solve quadratic equations by factorization?

Consider the equation x^2+5x+6=0. In order to factorise this equation you first need to think of what numbers sum to make 5 (the coefficient of x) and whose product equals 6 (the number not multiplied by x). If you can't think of any pair of numbers which give those results, then the equation is unfactorizable, but still possible to solve. In this case, the equation can be factorised and the numbers are 2 and 3. Now the equation is factorised to (x+2)(x+3)=0, which can now be solved as either (x+2) or (x+3) must equal to 0. So, this gives two possible answers: x=-3 and x=-2.

RF

Related Maths GCSE answers

All answers ▸

Factorise fully X^2 - 6X + 8


Solve the equation 2X^2 + 5X + 2 = 0 stating clearly the number of roots


A right-angled triangle has an adjacent of (x + 1) and (x - 1). (a) Find the length of the hypotenuse in terms of x. (b) Explain why the triangle can't be an isoceles triangle.


A plane travels at 213 miles per hour. Work out an estimate for how long, in seconds, the plane takes to travel one mile.