It is unclear what the question is?
Line A has a gradient of 3 and a y-intercept of -7
The equation of line A is y = 3x - 7
A line parallel to A passing through P will have the form y = 3x + c
Substitute the values of x and y at P(2,7)
7 = 3 x 2 + c
c = 1
Equation of parallel line through P is y = 3x + 1
A line perpendicular to A through P will have a gradient of -1/3
7 = -1/3 x 2 + c
c = 7 + 2/3
Equation of line perpendicular to A through P is y = (-1/3)x + 7 2/3
You may prefer the c value as the improper fraction 23/3
