Answer :
[tex]\bf g(x) = -0.5x^2+3x+4\qquad g(x)=-5\qquad thus
\\ \quad \\
-5=-0.5x^2+3x+4\implies \cfrac{1}{2}x^2-3x-9=0\leftarrow \times 2\textit{ both sides}
\\ \quad \\
x^2-6x-18=0[/tex]
solve for "x"
solve for "x"