I'll answer 3 of these questions.
For future notice, make sure to limit yourself to asking at most, 3 individual questions per question. :)
1) r/10+4=5
Subtract both sides by 4.
(r/10+4)-4=(5)-4
r/10=1
Multiply both sides by 10.
(r/10)*10=(1)*10
r=10
2) n/2+5=3
Subtract 5 from both sides.
(n/2+5)-5=(3)-5
n/2=-2
Multiply both sides by 2.
(n/2)*2=(-2)*2
n=-4
3) 3p-2=-29
Add 2 to both sides.
(3p-2)+2=(-29)+2
3p=-27
Divide both sides by 3.
(3p)/3=(-27)/3
p=-9
Hope this helps.
-Benjamin