CASE 1
The Question is: d = A + ( D / C2 ) where 'd' is the constant with dimensional formula [ L2 ].
So, the dimensions of ( D / C2 ) = Dimensions of A = [ L2 ].
Therefore, the dimensions of C2 = Dimensions of ( D / A ) = [ M L - 5 ]
==> Dimensions of C = [ M1/2 L - 5/2 ]
CASE 2
The Question is: D = ( A + d ) / C2 where 'd' is the constant with dimensional formula [ L2 ].
So, the dimensions of C2 = Dimensions of ( A + d ) / D = [ L2 ] / [ M L- 3 ] = [ M -1 L5 ].
==> Dimensions of C = [ M -1/2 L5/2 ]