Answer :
let'sWe are to find the zero's of the function
[tex]h(x)=x^2+3x-18[/tex]i.e the values of x for which
[tex]x^2+3x-18=0[/tex]Let's factorize this expression to obtain that;
[tex]\begin{gathered} x^2+3x-18=0 \\ \text{lets look for factors that sum to +3 and multiply to get -18. This is +6 and -3, so;} \\ x^2+6x-3x-18=0 \\ x(x+6)-3(x+6)=0 \\ (x-3)(x+6)=0 \end{gathered}[/tex]We see that the function h(x) is zero for x = 3 or x = -6