Question

11. rewrite the function in the form y=a (1+r)*

Answer 1

Problem 10

The two functions are inverses of each other. Why? Because we can think of f(x) = (x-7)/(-2) as y = (x-7)/(-2).

Swap x and y to get x = (y-7)/(-2). Solving for y leads to y = -2x+7 showing that g(x) = -2x+7 is the inverse of f(x) = (x-7)/(-2). This process can be done in reverse to get the same result.

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Problem 11

y = a(6)^(t/2)

y = a( 6^(1/2) )^t

y = a(2.4494897)^t

y = a( b )^t

where b = 6^(1/2) = 2.4494897 approximately

Set b equal to 1+r and solve for r

1+r = 2.4494897

r = 2.4494897-1

r = 1.4494897

This rounds to about r = 1.45

The r value is the decimal form of the percentage, which means we move the decimal point over two spots to the right to get 145% approximately

Answers:

The equation is roughly y = a(1 + 1.4494897)^t

The growth rate is approximately 145%

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Problem 12

You have the correct answer. Nice work.

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Problem 13

You are very close to the correct answer. However, you're missing the base of the log.

The answer should be $\log_{49}(343) = \frac{3}{2}$. So you'll need to write in a small "49" under the log.

The general rule is that exponential equations in the form $b^x = y$ are equivalent to the log version of $\log_{b}(y) = x$. For each equation, b is the base. The idea of logs is to isolate the exponent.