Question

Solve equations with 3 variables

Answer 1

add up equation 1 and 2 to eliminate b
(a+b)+(-b+c)=3+3 => a+c=6 
subtract this new equation from the third equation:
(a+2c)-(a+c)=10-3 =>c=4
plug in c=4 in a+c=6 =>a=2
a+b=3, a=2 =>b=1