#### Answer

$C=7$

#### Work Step by Step

Since the three lines are concurrent, the three lines all intersect at one point.
We can rearrange the equation of the second line:
$2x+y = 5$
$y = 5-2x$
We can replace $y$ in the third equation to find the x-coordinate:
$x-y=4$
$x-(5-2x) = 4$
$x-5+2x=4$
$3x = 9$
$x = 3$
We can find the y-coordinate:
$y = 5-2x$
$y = 5-2(3)$
$y = 5-6$
$y = -1$
We can find the value of $C$:
$3x+2y=C$
$C = 3(3)+2(-1)$
$C = 9-2$
$C=7$