The ellipse x^2/49+y^2/b^2=1 has foci at (5,0) and (-5,0).

For A i got 7 by doing sqrt 48 but B im a bit confused. I did sqrt(a^2-c^2)=sqrt(7^2-5^2)=sqrt24=2sqrt6. So would the value of be just 2sqrt6 or do I need to do some other step?

x^2/49  + y^2/b^2  = 1

a  = 7       =   length of semi-major  axis

c  = 5

b =   sqrt   (7^2  - 5^2)   = sqrt (24)  =   2sqrt (6)

Good job , WDIPT    !!!!