Step 1) Solve the first equation for #y#:
#x + y - color(red)(x) = 3 - color(red)(x)#
#x - color(red)(x) + y = 3 - x#
#0 + y = 3 - x#
#y = 3 - x#
Step 2) Substitute #3 - x# for #y# in the second equation and solve for #x#:
#3x + y = 5# becomes:
#3x + 3 - x = 5#
#3x - x + 3 = 5#
#2x + 3 = 5#
#2x + 3 - color(red)(3) = 5 - color(red)(3)#
#2x + 0 = 2#
#2x = 2#
#(2x)/color(red)(2) = 2/color(red)(2)#
#(color(red)(cancel(color(black)(2)))x)/cancel(color(red)(2)) = 1#
#x = 1#
Step 3) Substitute #1# for #x# in the solution to the first equation at the end of Step 1 and calculate #y#:
#y = 3 - x# becomes:
#y = 3 - 1#
#y = 2#
The solution is: #x = 1# and #y = 2# or #(1, 2)#
