If  $y=\frac{GI{M}^2}{E^2}$,  E  = energy,  G  = Gravitational constant,  I  = Impulse and  M  is mass, then the dimension of  y  is same as

Dear friend,
The given equation is
Y=GIM²/E²
Thus,
The dimensions of G are not possible as it a constant.
Here the dimensions all other are as follows
E²=[L⁴ M² T^-2]
I =[L¹ M¹ T^-1]
M²=[L^0 M² T^0]

Thus,
Y=[L¹M¹T^-1][L^0M²T^0]/[L⁴M²T^-4]
Therefore by applying law of indices
We get the dimensions of y as
Y=[L^-3 M¹ T³]


Hope it helped