Answer
Please see the graph.
$x=6, -12$
Work Step by Step
$.5x^2+3x-36=0$
$x=(-b±\sqrt {b^2-4ac})/2a$
$x=(-3±\sqrt {3^2-4*.5*(-36)})/2*.5$
$x=(-3±\sqrt {9-2*(-36)})/1$
$x=(-3±\sqrt {9-2*(-36)})$
$x=(-3±\sqrt {9+72})$
$x=(-3±\sqrt {81})$
$x=(-3±9)$
$x=-3+9$
$x=6$
$x=-3-9$
$x=-12$