My instructor writes this on our review sheet, "An ellipse with vertices (-7,2) and (1,2) passes through (-1,-1). Write the equation."

Since the vertices have y-coordinate 2, I know the major axis is horizontal. I use:

(x-h)^2(y-k)^2

a^2 + b^2

So I find the center (-3,2)

I also find a= 4

So, how do I find b^2? My instructor did not provide the minor axis or "c."

So far I have:

(x+3)^2+(y-2)^2Thank You, Kay

16 b^2