Simple...
you have: [tex] \frac{18-2*5}{15+3(-3)} [/tex]
To solve this just go slowly..simplify everything out-->>
[tex] \frac{18-2*5}{15+3(-3)} = \frac{18-10}{15+3(-3)} [/tex]
[tex] \frac{18-10}{15+3(-3)} = \frac{8}{15+3(-3)} [/tex]
[tex] \frac{8}{15+3(-3)} = \frac{8}{15+-9} [/tex]
[tex] \frac{8}{15+-9} = \frac{8}{6} [/tex]
[tex] \frac{8}{6} = \frac{4}{3} [/tex]
Answer is [tex] \frac{4}{3} [/tex].
Thus, your answer.