The answer is y = 1/3x + 1
To get the equation for line L, we need two things: the y-intercept and the slope. The slope for perpendicular lines is the negative reciprocal of the given slope, so if it was 2 the negative reciprocal would be -1/2 and if the slope was -3/2 the negative reciprocal would be 2/3. The negative reciprocal of -3 is 1/3, which is our slope. To get the y-intercept, you just substitute in the values of the point, so:
3 = (1/3 × 6) + C
3 = 2 + C
C = 1