-3x + 7y = -16 . . . (1)
-9x + 5y = 16 . . . .(2)
(1) x 3 => -9x + 21y = -48 . . . (3)
(2) - (3) => -16y = 64 . . . (4)
Required equivalent system of equations is
-9x + 5y = 16
-16y = 64
0.99999696 is your answer I am pretty sure.
Actually I didn't see the (-5, -27), the answer would be -2.
To find the total length of the two copper pipes, we need to add them together.
2 5/12 + 3 7/12 = 5 12/12
Since 12/12 = 1 or a whole, we can simplify this further.
5 12/12 = 6
Hope this helps!