Answer
$\color{blue}{y=1.5x+9}$
Work Step by Step
RECALL:
(1) The slope-intercept form of a line's equation is $y=mx+b$ where $m$=slope and $(0, b)$ is the line's y-intercept.
(2) The slope is the rise (change in $y$) over run (change in $x$).
The given graph has a y-intercept of $(0, 9)$.
This means $b=9$.
Note that from $(0, 9)$ to the other point on the line $(2, 12)$:
rise =$12-9=3$
run = $2-0=2$
Thus, the slope of the line is $\dfrac{rise}{run} = \dfrac{3}{2} = 1.5$.
Therefore, the equation of the line in slope-intercept form is $\color{blue}{y=1.5x+9}$.