Which relation is a function ?

For each proportion find the unknown number x 1/5/8=×/15

Which describes the difference between the graph of f(x)=x^2 and g(x)=-(x^2-2)

The radius of the circle below intersects the unit circle at (3/5,4/5). what is the approximate value of theta? 0.6 radians 1.0 radians 36.9 degrees 53.1 degrees