Question

If f(x)=x^2-4, then f(x+3)=?

Answer 1

Answer:

x = 2

Step-by-step explanation:

When solving an equation like this, you can act as if f(x) is equal to 0. So in this case: $x^{2} - 4 = 0$. Add 4 to both sides of this equation: $x^{2} = 4$. Now you can find the square root ($\sqrt{x}$) of both sides: $x = 2$.

Plug the value of $x$ into the second equation: $f(x+3)=f(5)$. This now turns the value of $f(x)=x^{2} -4$ into $f(5) = 5^{2} -4$. This equation then ends up equaling $f(5) =25-4=21$.

The answer is then 21.