b² = a²(1-e²)
and the equation for an ellipse is
x²/a² + y²/b² = 1
We're told the Ellipse E has equation
x²/2² + y²/3² = 1
so 9 = 4(1-e²)
4e² = -5
which you cant do, because that would be a complex number. BUT howcome you can get around this by swapping the values for a and b round. That also means that the focus has now transferred to the y axis, rather than the x, as foci as (ae,0) and now a = b?