c for the 2 equations under the sqrt u know the expression under the root>=0 to have real solutn...

for the one on LHS domain is (0-infinity,2]U[5,infinity)

and on RHS its [2,5]

so for these 2 equations to be simultaneously satisfied either

x=2 or x=5

but if u put x=5 LHS <RHS

hence x=2

i hope u have understood...........