Look at the picture it explains the answer
If a plane flies an average of 325 miles per hour, to find out 7 hours you will need to times 325 by 7.
325 x 7 = 2275.
therefore the flight for 7 hours was 2275 miles.
Assuming the equation is x^2 + y^2 = 1, then that's a circle, with radius 1, centered on the origin [0,0].
So there are two tangents at x = 0. They are y = 1, and y = -1 (horizontal lines).
There is one tangent at x = 1. It is x = 1 (a vertical line).
There is no tangent at x = 35, because the original equation has no solution at x = 35.
