Posted by cbse 8th on Saturday, July 12, 2014 at 12:59am.
I'll solve one, and will let you try the others as exercise.
x=(4/5)(x+10)
multiply by (5/4) on both sides:
5x/4 = x+10
subtract x from each side
5x/4-x =10
x/4=10
x=40
Check:
(4/5)(x+10)=(4/5)(40+10)=40=x ok.