Solve the quadratic equation [math]x^2 + 3x – 4 = 0[/math]
We can use the quadratic formula:
[math]x = \frac{-b \pm \sqrt{b^2 – 4ac}}{2a}[/math]
We will let [math]a = 1[/math], [math]b = 3[/math], [math]c = -4[/math]
Substituting the values into the equation:
[math]x = \frac{-3 \pm \sqrt{3^2 – 4(1)(-4)}}{2(1)}[/math]
Simplify:
[math]x = \frac{-3 \pm \sqrt{9 + 16}}{2}[/math]
[math]x = \frac{-3 \pm \sqrt{25}}{2}[/math]
Split the fraction:
[math]x = \frac{-3 + 5}{2}[/math], and [math]x = \frac{-3 – 5}{2}[/math]
Solutions:
[math]x = 1[/math] and [math]x = -4[/math]