Find the equation of the line:
a. Parallel to the line y = 3x − 5, passing through the point (1, 7)
b. Parallel to the line x + 2y = 6, passing through the point (4, −6)
c. Perpendicular to the line y = 2x − 3, passing through the point (6, 1)
d. Perpendicular to the line 2x − 3y = 12, passing through the point (8, −3).