Answer:
5y + x = 5c
Step-by-step explanation:
Rewriting the equation, 15x - 3y = 7,
3y = 15x - 7
y = 5x - 7/3. The gradient is 5. The gradient of the perpendicular line is -1/5
The equation of the perpendicular to 15x - 3y = 7 passing through (0,c) is
(y - c)/(x - 0) = -1/5
(y - c)/x = -1/5
y - c = -x/5
y = -x/5 + c
5y = -x + 5c
5y + x = 5c
