Please answer my quesToon

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

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.

Which equation represents a direct linear variationa. y=x2b. y=2/5xc. y=1/xd. y=x+3