What is the equation of the ellipse with e=3/4

For

x^2/a^2 + y^2/b^2 = 1

e = c/a = 3/4
so let c=3 and a=4

also we know that for the above,
b^2 + c^2 = a^2
b^2 + 9 = 16
b^2 = 7

so x^2/16 + y^2/7 = 1 is one such equation