Explanation: I would use the substitution method for this system
because one of the variables, x, is already isolated in the first equation.
Since our first equation states that x = 12 - y, 12 - y can be substituted
in for x in the second equation which becomes 2(12 - y) + 3y = 29.
Now we can solve this equation by first distributing the 2
through the parentheses to get 24 - 2y + 3y = 29 and you
should be able to easily finish solving from here to get y = 5.
Now substitute a 5 back in for the first equation to get
x = 12 - (5) or x = 7 which means that our solution is (7, 5).