Answer
$x=8$
$x={-\dfrac{15}{2}}$
Work Step by Step
$x=\dfrac{-b±{\sqrt {b^{2}-4ac}}}{2a}$ and $2x^{2}-x-120=0$.Therefore, $a=2$,$b=-1$ and $c=-120$
Substitute the values:
$x=\dfrac{-(-1)±{\sqrt {-1^{2}-4(2)(-120)}}}{2(2)}$
=$\dfrac{1±{\sqrt {1-(-960)}}}{4}$
=$\dfrac{1± {\sqrt {961}}}{4}$
=$\dfrac{1±31}{4}$
Separate the equation into plus and minus equations:
$x=\dfrac{1+31}{4}=8$
$x=\dfrac{1-31}{4}={-\dfrac{15}{2}}$
