Question

find all the real zeros of the polynomial function f(x)=49-x^2

Answer 1

y = 49 - x^2
Because we are looking for "zeros", we are looking for all the points at which y=0.
0 = 49 - x^2
Let's multiply both sides by -1 for easier calculations,
0 = x^2 - 49
Add 49,
49 = x^2
x = sqrt[49] = +-7

Answer 2

the answer is 7. :)