I need help! Really bad a math.

Answer:
12
Step-by-step explanation:
Substitute -18 into the equation
h(-18) = 15 +(-18)/6
h(-18)= 15 + (-2)
h(-18)= 15-2
h(18)=12
12 is the final answer
[tex]\\ \sf\longmapsto h(-18)[/tex]
[tex]\\ \sf\longmapsto 15+\dfrac{-18}{6}[/tex]
[tex]\\ \sf\longmapsto 15+(-3)[/tex]
[tex]\\ \sf\longmapsto 15-3[/tex]
[tex]\\ \sf\longmapsto 12[/tex]