Solve $LaTeX: \displaystyle x^{2} + 17 x + 72=0$

Since $LaTeX: \displaystyle a=1$ we need to find factors of $LaTeX: \displaystyle 72$ that add up to $LaTeX: \displaystyle 17$ . The factors are $LaTeX: \displaystyle 9$ and $LaTeX: \displaystyle 8$ . This gives $LaTeX: \displaystyle (x + 9)(x + 8)=0$ . The solutions are $LaTeX: \displaystyle x = -9$ and $LaTeX: \displaystyle x = -8$