Which of the equations below represents a line parallel to the y-axis? a)x=-9 b)x=9y c)x=y d)x=-y

Given that y varies directly to the square root of (x + 1), and that y = 1 when x = 8,(a)express y in terms of .x,(b)find the value of y when x = 3,(c)find the value of x when y = 5.