X + 3y = 7
x = -3y + 7
2x + 4y = 8
2(-3y + 7) + 4y = 8
-6y + 14 + 4y = 8
-2y = 8 - 14
-2y = - 6
y = -6/-2
y = 3
x + 3y = 7
x + 3(3) = 7
x + 9 = 7
x = 7 - 9
x = -2
solution is (-2,3)
Let t is the amount of time that the gas is leaking (hour), g is the total of the gas leak.
g = 3t.
Plug them in... -4=x -5=y
-3x-4+-6=6 (check)
-3x-4=12-6=6 (ordered pair works with this equation)
-2x-4+-6=-8 (check)
-2x-4=8-6=2 (ordered pair does not work with this equation)
Therefore the ordered pair IS NOT the solution.
Hope this helps :)