Solve $LaTeX: \displaystyle x^{2} - 5 x - 36=0$

Since $LaTeX: \displaystyle a=1$ we need to find factors of $LaTeX: \displaystyle -36$ that add up to $LaTeX: \displaystyle -5$ . The factors are $LaTeX: \displaystyle 4$ and $LaTeX: \displaystyle -9$ . This gives $LaTeX: \displaystyle (x + 4)(x - 9)=0$ . The solutions are $LaTeX: \displaystyle x = -4$ and $LaTeX: \displaystyle x = 9$