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

User Paulochf
by
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1 Answer

10 votes

Answer:

x = 2

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 (
√(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.

User Blind
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4.4k points