(a) The line passes through the axes at the point (0, 3) and (1.5, 0), so its slope is
m = (0 - 3)/(1.5 - 0) = -3/1.5 = -2
The y-intercept is b = 3.
Then the line has equation
y = -2x + 3
(b) Any line perpendicular to the given one has a slope of -1/(-2) = 1/2. The perp. line that passes through (3, -1) has equation
y - (-1) = 1/2 (x - 3) ===> y = 1/2 x - 5/2