Question 160050
add 1st eqn and 3rd eqn __ 3x+9y=36 __ x+3y=12 __ x=12-3y


multiply 1st eqn by 2, then add 2nd eqn __ 5x+7y=44


substituting __ 5(12-3y)+7y=44 __ 60-8y=44 __ y=2


substituting __ x=12-3(2) __ x=6


substituting __ (6)+5(2)-z=16 __ z=0