Given,
An ellipse with centre (1,0) and latus rectum of length 21 have its major axis along x-axis
And its minor axis subtends an angle 60∘ at the foci,
So, on plotting the diagram we get,

Now from diagram we get,
a2b2=21⇒b2=4a...(1)
And tan30∘=aeb
⇒(31)2=(aeb)2
⇒31=a2−b2b2
⇒a2−b2=3b2
⇒b2=4a2.......(2)
Now from equation (1)&(2) we get,
⇒a=1,b2=41⇒b=21
Hence, (2a+2b)2=9