Find the linear approximation of the functionf(x) = √(25-x) ata= 0 and use it to approximate the numbers √24.9 and √24.99.

L(x)=

(I used this to get the√24.9 and √24.99; (4.99, 4.999 respectively),but...

I put this in for part a, and it was marked wrong. A=0, but if I put (x-0) instead of (x-25) it becomes a number greater than 5, which won't make sense considering you plug in a number lower than 25.