7 = r^1/2 is the same as saying 7 = square root of r. So, to get rid of the square root sign on the r, you need to square it, and when you do something to one side of the equation, you have to do the same to the other side. So after squaring both sides, you get 49 = r.
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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 
The number of lateral faces for a hexagonal prism or pyramid is 6.
<h3>What is a
prism?</h3>
A prism is a three dimensional figure consisting of pair of opposite bases and lateral faces which are parallelogram.
Given that the base off the prism has two sides of length 3 inches and four sides of length 2 inches. Hence the base is hexagonal. The lateral faces would be 6.
The number of lateral faces for a hexagonal prism or pyramid is 6.
Find out more on prism at: brainly.com/question/23963432
The formula for the area of a trapezoid is 1/2 (b1 + b2) h
So, take your b1 and b2, 12 and 6, and add them together. You get 18.
Divide this by 2, and you get 9.
Now, multiply 9 by your height, which is 4.
9 x 4 = 36.
The area of the trapezoid is 36 square inches.