The slope of the presented equation is -3. This is the coefficient of x. The line perpendicular to such is its negative inverse, 1/3
This equation is in the slope-intercept format of...
m is the slope.
b is the y-intercept, the value of y when x=0.
We can proceed by plugging-in the coordinate provided and thereby establishing b.
Or, we can proceed by using the point-slope formula...