Question 227569
adding the 1st and 3rd eqns ___ 5A + 5C = 20 ___ A + C = 4 ___ A = 4 - C


substituting into 2nd eqn ___ 4 - B = 2 ___ 2 = B


substituting into 1st eqn ___ 2(4 - C) + 2(2) + 3C = 15 ___ 8 - 2C + 4 + 3C = 15 ___ 12 + C = 15 ___ C = 3


substituting ___ A = 4 - (3) = 1