We are given an equation:

This is an equation of a circle. General form of a circle equation is:

Where:
a = x coordinate of a center
b = y coordinate of a center
r = radius of a circle
Motion detector can detect person anywhere within a boundary. The greatest distance at which detector can detect is at the edge of a circle. That distance, between detector and edge of circle, is equal to radius.
From the equation we have:

The greatest distance at which person can be detected is 4ft.
A.0 I don't actually know
Answer:
8-14 or -6
Step-by-step explanation:
By comparing the given shape with easier ones like triangles and rectangles we will see that the area of the shape is 8 square units.
<h3>
How to simplify the shape.</h3>
So the given shape is a little bit complex, but you can actually see that it is a triangle with a base of 8 units with a height of 4 units, where a rectangle of 2 in by 3 in was removed, and also removed a triangle of height of 2 inches and base of 2 inches.
Remember that:
- A triangle of height H and base B has an area = B*H/2
- A rectangle of length L and width W has an area = L*W.
Then the area of the given shape is:
A = 8*4/2 - 3*2 - 2*2/2
A = 16 - 6 - 2
A = 8
So the given shape has an area of 8 square units.
If you want to learn more about areas, you can read:
brainly.com/question/14137384
Answer:
D) 3x^2 - 12
Step-by-step explanation:
Using PEMDAS;
There is no need to evaluate the part of the equation (x^2 - 8) because is no need to, as it is already in its simplest form.
We must evaluate the part of the equation continuing with, "- (-2x^2+4)," as it is not in its simplest form.
Evaluating "- (-2x^2+4)":
Step 1: Distributing the negative
Once distributing the negative symbol amongst the values within the parenthesis according to PEMDAS, we get "2x^2 - 4" as the product.
Step 2: Consider the rest of the equation to evaluate
Since the part of the equation is still in play here as it is a part of the original equation to be solved, we must evaluate it as a whole to get the final answer.
Thus,
x^2 -8 + 2x^2 - 4 = ___
*we can remove the parenthesis as it has no purpose, since it makes no difference.
Evaluating for the answer, we get,
x^2+2x^2 + (-8 - 4) = 3x^2 - 12
Hence, the answer is D) 3x^2 - 12.