To find the zeros of the function 
we need to factorize the expression.
a nice way to factorize
, if possible, is by completing the square as follows:
now we use the difference of squares formula
:
![(x-3)^{2}- 5^{2}=[(x-3)+5][(x-3)-5]=[x+2][x-8]](https://tex.z-dn.net/?f=%28x-3%29%5E%7B2%7D-%205%5E%7B2%7D%3D%5B%28x-3%29%2B5%5D%5B%28x-3%29-5%5D%3D%5Bx%2B2%5D%5Bx-8%5D)
finally, we combine the results:
the zeros of f, are the values of x which make f(x)=0,
they are x=0, x=-2 and x=8
Answer: {-2, 0, 8}
a nice way to factorize
now we use the difference of squares formula
finally, we combine the results:
the zeros of f, are the values of x which make f(x)=0,
they are x=0, x=-2 and x=8
Answer: {-2, 0, 8}