Recall that

Dividing both sides by cosh²(x) gives

Also, recall the identity

Then

If we want to has 100 in the denominator we have to divide numerator and denominator by 2. Then total value of fraction doesnt change.

Now read the fraction, its 23 hundreds, now just write as decimal, so,
0.23
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Answers:</h3>

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Work Shown:
Part 1

Notice how I replaced every x with g(x) in step 2. Then I plugged in g(x) = x^2+6 and simplified.
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Part 2

In step 4, I used the rule (a+b)^2 = a^2+2ab+b^2
In this case, a = sqrt(x-1) and b = 5.
You could also use the box method as a visual way to expand out 
6x2, because using pemdas, 2x2= 4 then 4x3=12. The answer must equal 12, and 6x2 does.
Answer:
The answer is 415 because it is already in standard notation.