Distance formula issues

I don't understand. I'm doing the distance formula for P1=(5,-2)  P2=(4,5) and I get sqrt50 as the answer which they say is in the wrong form? The example is that P1=(4,-3)  P2=(2,5)=sqrt68=2sqrt17... So how do I get a similar answer with sqrt50? Every time I plug it in the calculator I get the answer 7.071.......