Find an equation in standard form for the ellipse with the vertical major axis of length 18 and minor axis of length 16.

Let us assume then that the center is the origin. If the major axis is 18, then a = 9 and a^2=81. If the minor axis is 16, then b = 8 and b^2=64. Now you can write the equation. Remember that this ellipse is vertical and so a^2 goes under y^2