#### Answer

$2\frac{3}{7}$

#### Work Step by Step

When $x=\frac{3}{4}$ and $y=-\frac{4}{7}$:
$4x+y$
$=4(\frac{3}{4})+(-\frac{4}{7})$
$=(\frac{4}{1}\times\frac{3}{4})-\frac{4}{7}$
$=(\frac{1}{1}\times\frac{3}{1})-\frac{4}{7}$
$=\frac{3}{1}-\frac{4}{7}$
$=\frac{21}{7}-\frac{4}{7}$
$=\frac{17}{7}$
$=2\frac{3}{7}$