first one
remember
a/b=c/d also can be written as
ad=bc
so
first one can be rewritten as
3x=96
divide both sides by 3
x=32
2nd ones we can just times both sides by 5 to get
x=50/12
3rd one we times 12 both sides to get
x=8
4th one we translate to
4x=63
divide by 4
x=63/4
5th one we translate to
99=5x
divide by 5
99/5=x
6th one we times 21 both sides
6=x
7th one we times both sides by 16
14=x
last one we translate to
45=3x
divide 3
15=x
