The graph represent a horizontal ellipse with center ,(h,k)=(-1,3)
Length of major axis, 2a =8-(-10) = 18
Therefore, a = 9
And length of minor axis, 2b =5-1 =4
Therefore b=2
The formula that we have to use to find the vertices
(h+-a,k)
(-1+-9,3) = (-1-9,3),(-1+9,3) = (-10,3),(8,3)