-2/3-n=-3/4, -2/3+3/4=n, (-8+9)/12=n, so n=-1/12; or did you mean: -2/(3-n)=-3/4? If so, 8=3(3-n), 8=9-3n, 3n=1, n=1/3.
k-3=-10, k=3-10=-7.
-3/2+4x=113/10,
4x=113/10+15/10=128/10=64/5,
x=16/5.
If the numbers are 2m-2, 2m, 2m+2 then their sum is 84=6m, m=14, so the numbers are:
26, 28, 30 the smallest of which is 26.