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What is the output for x = -1

What is the output for x = -1-example-1
User Kuzma
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1 Answer

3 votes

Answer:

f(-1) = 16

Explanation:

"output" and the f(x) setup just means to plug in -1 in place of x and calculate.

For the function f(x) = 12(3/4)ˣ you have to already know that once you put that -1 in place of x that the -1 power only goes to the 3/4, not the 12 and also what to do with a negative exponent.

Exponent rules are just shortcuts. The shortcut to know here is that the -1 exponent will flip the 3/4 over and make it 4/3 (there are math reasons for this, it's not random. But that's how it works)

So now you have

f(-1) = 12(3/4)⁻¹ which becomes

f(-1) = 12(4/3)

Now you need to know how to multiply with fractions. Here you have a whole, big number times a fraction, which is:

"big num×top all over bottom"

So multiply the 12 times the 4 and put it over the 3

f(-1) = 48/3 = 16

(or you can "cancel" the 12 with the 3 and get 4×4, which is 16, so it comes out the same)

[SKIP TO HERE IF YOU DON'T CARE WHY]

f(x) = 12(3/4)ˣ

f(-1) = 12(3/4)⁻¹

f(-1) = 12(4/3)

f(-1) = 16

User Marcj
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