a+b+c=790,a-c=480
b=70.
a+70+c=790
a+c=790-70
a+c=720
a-c=480
--------------
2a=720+480
2a=1200
a=600
600-c=480
c=600-480
c=120
d=333
e+f=184 d-(e-f)=317
333-(e-f)=317
-e+f=317-333
-e+f=-16 /-1
e-f=16
e+f=184
--------
2e=16+184
2e=200
e=100
100-f=16
f=100-16
f=84
