Answer
$a.\quad y= \displaystyle \frac{4}{3}x$
$b.\quad $slope: $\displaystyle \frac{4}{3}, \quad $y-intercept: $0$
$c.\quad $see graph below
.

Work Step by Step
$ a.\quad$
$3y=4x$
... divide with 3
$y= \displaystyle \frac{4}{3}x$
$ b.\quad$
Comparing to $y=mx+b,$
the y-intercept is $0$,
the slope is $m=\displaystyle \frac{4}{3}\quad=\frac{\text{change in y}}{\text{change in x}}$
$ c.\quad$
To obtain a second point, starting with $(0,0)$,
change x by $3$, y by $4\quad\rightarrow\quad(3,4)$.
Draw a line through the two points.