Solve $LaTeX: \displaystyle x^{2} - 3 x - 4=0$

Since $LaTeX: \displaystyle a=1$ we need to find factors of $LaTeX: \displaystyle -4$ that add up to $LaTeX: \displaystyle -3$ . The factors are $LaTeX: \displaystyle 1$ and $LaTeX: \displaystyle -4$ . This gives $LaTeX: \displaystyle (x + 1)(x - 4)=0$ . The solutions are $LaTeX: \displaystyle x = -1$ and $LaTeX: \displaystyle x = 4$