f1....

1. 720=400{1+16(n)/200}
720=400+2n/25(400)
720=400+32n
320=32n
n=10

2. 5=16/c+(-3)
5+3=16/c
8=16/c
c=2

3. 1/14=1/7-1/j
1/7-1/14=1/j
1/14=1/j
j =14

4. 1/20=1/4-1/r
1/4-1/20=1/r
1/5=1/r
r=5

5. 24=1/6(12)(g)
24=2g
g =12

6. -20=-5/2-h
-20+5/2=-h
h =35/2

7. 6(2)=m+3/4
12-3/4=m
m =45/4

8.60=1/2(3)(c-4)
60=3/2c-6
66=3/2c
c =44