First I will tell you the formula for this, then I will show how we got the formula, then the answer.
Formula -> (x+a)(x-a)=x^2-a^2
We can find this by expanding the 2 ( )
(x+a)(x-a)=x^2+ax-ax-a^2=x^2-a^2
Now we can use this to solve your problem, the 5 is the a in the formula.
(x+5)(x-5)=x^2-5^2=x^2-25. Therefore choosing the 3rd answer choice.
