Answer:
or 
Step-by-step explanation:
You need to complete the square before you can take the square root of both sides.

Subtract 10 from both sides.

To complete the square, you need to add the square of half of the x-term coefficient to both sides.
The x-term coefficient is 7. Half of that is 7/2. Square it to get 49/4. Now we add 49/4 to both sides of the equation.



Now we use the square root property, if
, then



or
or 
or 
Answer:
7⁷
Step-by-step explanation:
a^(1/7) = 7
a = 7⁷
The range of a function is the set of possible values that can be obtained from the dependent variable. The range of the function is: 
Given that:


Let the number of months be t. So, the function C(t) is calculated as follows:



The range is calculated as follows:
The smallest possible value of t is 0 i.e. when no monthly subscription is done.
So, we have:

And the highest is
i.e. for a large value of t
So, we have:

Hence, the range of the function is:

Read more about range of functions at:
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