First find the slope:
The slopes of perpendicular lines must multiply to -1.
-9m = -1 ----> m = 1/9
Next, use point-slope form:
y - y1 = m(x-x1) , where given point (0,5) is (x1,y1)
y - 5 = (1/9)(x - 0)
Finally, solve for y to put it in slope-intercept form:
y = (1/9)x + 5