## College Algebra (10th Edition)

$\color{blue}{y=\dfrac{1}{2}x}$
RECALL: $y=mx+b$, where $m=slope$ and $b$ = y-intercept. The given line has a y-intercept of $0$, so its tentative equation is: $y=mx + 0 \\y=mx$ To find the value of $m$, substitute the x and y values of the point $(2, 1)$ into the tentative equation to obtain: $y=mx \\1 = m(2) \\1=2m \\\frac{1}{2}=m$ Thus, the equation of the line is $\color{blue}{y=\dfrac{1}{2}x}$.