Question

a+b=700 b+c=500 a+c=800 determina a,b,c

Answer 1

a+b=700

b+c=500

a+c=800

a+b+b+c+a+c=2a+2b+2c=2(a+b+c)=700+500+800

2(a+b+c)=2000

a+b+c=1000

a=1000-500

a=500

b=1000-800=200

c=1000-700=300

Answer 2

a+b=700
500+200=700
b+c=500
200+300=500
a+c=800
500+300=800
a+b+c=500+200+300=1000