What is the nth term for 1 7 15 25 37

In the image, point a marks the center of the circle. which two lengths must form a ratio of 1 : 2? (options are in the images since thought they were harmful phrases)

How many solutions does the nonlinear system of equations graphed bellow have?

Consider u = {x|x is a negative real number}which is an empty set? o {x|x eu and x has a negative cube root}o {x|x eu and x has a negative square root}{x|x eu and x is equal to the product of a positive number and -1}{x|x eu and x is equal to the sum of one negative and one positive number?