Imagine math help, which one is it?

The table represents a function f(x). what is f(3)? a.-9 b.-1 c.1 d.9

X+ y = 5 ; x - y =3 solve using linear combination

Sketch the region enclosed by the given curves. decide whether to integrate with respect to x or y. draw a typical approximating rectangle and label its height and width. y= 5x, y=7x^2then find the area s of the region.