Given: q=7m + 3n, r= 11 - 2m, s= n + 5, and t= -m - 3n + 8

simplify r - [s + t]

R = 11-2m
S = n+5
T = -m-3n+8

Add up S and T to get...
S+T = (n+5)+(-m-3n+8)
S+T = n+5-m-3n+8
S+T = -m+(n-3n)+(5+8)
S+T = -m+(1n-3n)+(5+8)
S+T = -m+(-2n)+(13)
S+T = -m-2n+13

Subtract that result from R
R - [S + T]
11-2m - [-m-2n+13]
11-2m +m+2n-13
(-2m+m) + (2n) + (11-13)
(-2m+1m) + (2n) + (11-13)
(-1m) + (2n) + (-2)
-m + 2n - 2


The final answer is -m + 2n - 2