Solve the simultaneous equation, 3x + y = 8 and x + 3y = 12, to find a value for x and y.

Re arrange one of the equation to get a single variant answer. So, x = 12 - 3y. Substitute this into the other equation, so 3 (12-3y) + y = 8. Expand this equation to form 36 - 9y + y = 8. Collect the y terms of the equation on one side, 8y = 28. Re arrange to get y = 28/8. Substitute this into the original equation x = 12 - 3y to get x = 12 - 3 (28/8), to get x = 12 - 84/8. Thus x = 12- 84/8 and y = 28/8.