Simple,
writing out the problem...
[tex] \frac{10-4x(6+5-1)}{15} [/tex]
Simplify it...
-4x(6+5-1)
-4x(11-1)
-4x(10)
-40x
Making it look like...
[tex] \frac{10-40x}{15} [/tex]
Cancel out the common factors...
Thus making the answer:
[tex]- \frac{2(4x-1)}{3} [/tex].