Please check

5n-30=-20
N=2

5=h/4+9
H=16

-m/3-2=10
M=-36

M/8+5.6=9.85
M=34

36-4r=24
R=3

14==-16-10n
N=3

-4x+7=-9
X=4

3y-6=20
Y=8 2/3

6n+16=36
N=3 1/3

14=-16-10n

n=-3

the others look good.