Question

What equation is equivalent to 9^x - 3 = 729?

Answer 1

Answer: 9^(x-3) = 9^3

Step-by-step explanation:

Realizing that 729 = 9^3, we can rewrite the equation ...

9^(x -3) = 729

as ...

9^(x -3) = 9^3 . . . . . . matches the second selection

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Recognizing that 9 = 3^2, a couple of other equivalent forms can be made.

(3^2)^(x -3) = (3^2)^3

3^(2x-6) = 3^6

or, taking the square root, ...

3^(x -3) = 3^3

None of these forms match any answer choices.

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The solution will be found by matching exponents:

x -3 = 3

x = 6