center of mass of a thin plate with a density function

Looking for somone to validate my answer or maybe tell me what Im doing wrong, I get an answer of x=0,y=98/5......my worksheet claims the answer is x=0,y=14

find the center of mass of the region bounded by y=49-x^2 and the x-axis with density of 7x^2

x=0 because its centered on the orgin

area is over the interval of -7 and 7

I get a mass of (1372p)/3; (p=density)

Mx=(268912p)/30

y=Mx/mass; y=98/5

From my understanding and how Im doing the problem the density cancels out, which is were Im confused on how it will affect my answer, thats were Im probably messing up but my textbook doesnt shine much light on problems with non-uniform density. Can someone please help me out?