Question 665449
a+b=7
b+c=9
a+c=8

a+b=7
b+c=9

subtract
a-c= -2
we have a+c=8

add the two
2a=6
a=3

if a=3 , a+b=7 so b=4
if b=4 , b+c=9 so c=5

a=3,b=4,c=5