Locate the foci of ellipse. Show your work.

X^2/36 + y^2/11 = 1

In this equation, 36>11 and so the ellipse has major axis along x axis

standard equation of ellipse with major axis is along x axis

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

the foci are at (ae, 0) and (-ae, 0)

eccentricity e is given by

ae=√ (a^2-b^2)

In this case ae=√ (36-11) = √25 = + / - 5

Focii are (-5,0) and (5,0)