When writing the equation keep in mind that 7 + x is said as a term that is squared so it has to be squared while it's still together; (7 + x)².
Answer:
y=10
Step-by-step explanation:
Substitute -4 in place of x
y = -4*-4-6
y=10
Answer: 
This is the shorthand way of writing 
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Work Shown:

The plus or minus is needed because squaring a negative leads to a positive. As another example, x^2 = 25 has x = 5 and x = -5 as the two solutions. Note that x^2 = (-5)^2 = (-5)*(-5) = 25.
Also, note that the 80 was broken up into 16*5. This was done to simplify the square root. We pull out the largest factor that's a perfect square.
So that's how we get to the solution set
. The curly braces tell the reader that they are dealing with a set.
Considering that 12 is a root of the function, the value of coefficient Q is of 12.
<h3>What does it means that x is a root of a function f(x)?</h3>
It means that f(x) = 0.
In this problem, the function is given by:
f(x) = x² - 13x + q.
Since 12 is a root, we have that f(12) = 0, hence:
12² - 13 x 12 + q = 0
q - 12 = 0.
q = 12.
More can be learned about functions at brainly.com/question/25537936
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It should be $57.30. I use a calculator for school but you just add 2.7% to 55.80 to find the answer.