Answers:

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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
