Solution assignment 03 Quadratic equations (abc-formula)

Solve:

$x^2-x-56=0$

We can factorize the left-hand side:

$(x-8)(x+7)=0$

and thus the solutions are:

$x_1=8$ or $x=-7$

We could get the same result by applying the $abc$ -formula:

$x_{1,2}=\displaystyle\frac{-(-1)\pm\sqrt{(-1)^2-4.1.-56}}{2.1}=\displaystyle\frac{1\pm15}{2}$