Question 165447
substitute the z value into the 2nd and 3rd eqns


-2x+5y+2(-4)=-34 __ -2x+5y=-26


x-2y+2(-4)=4 __ x-2y=12 __ multiplying by 2 __ 2x-4y=24


adding the equations __ -2x+5y+2x-4y=-26+24 __ y=-2


substituting __ x-2(-2)=12 __ x=8