Please put it in order

This circle is centered at the origin, and the length of its radius is 6. what is the circle's equation? a. x^2+y^2=36 b x^2+y^2=6 c x+y=36 d x^6+y^6=1

The function y= x - 4x+ 5 approximates the height, y, of a bird, and its horizontal distance, x, as it flies from one fence post to another. all distances are in feet. complete the square to find and interpret the extreme value (vertex). select two answers: one extreme value and one interpretation.

Can someone me and explain..will award brainlest!