Answer:
Third option. 
Step-by-step explanation:
For this exercise you need to remember one of the properties for exponents.
There is a property called the "Negative property of exponents" which states the following:
Where 
As you can observe,
is the reciprocal of 
In this case you have the following expression given in the exercise:

Observe the expression. As you can notice, the base "n" has a negative exponent, which is -6.
Therefore, applying the Negative property of exponents explained at the beginning of this explanation, you can simplify the expression.
Then, the simplified form of
is the one shown below:

Answer:
Length: 7
Width: 4
Step-by-step explanation:
We can create a system of equations for this problem, where
is the width and
is the length.
The perimeter of a rectangle is twice its length added to twice its width.

The length is 3 more than the width:

We can now substitute in
as
in the equation
.

Distribute the first terms:

Combine like terms:

Subtract 6 from both sides:

Divide both sides by 4:

Now we know that w = 4. We can now substitute this inside an equation to find
.

Hope this helped!
Answer:
y=-1/3x-17/3
Step-by-step explanation:
I assume you mean <em>perpendicular</em><em> </em>to x=-3.
In that case, we would flip and take the negative. A perpendicular slope would be x=-1/3
Now we plug the point (4,-7) into the equation
y=mx+b
y=-1/3x+b
-7=-1/3*4+b
-7=-4/3+b
b= -17/3
The whole equation would be:
y=-1/3x-17/3
<em>I hope this helps! :)</em>
Answer:
0.5, 80%
Step-by-step explanation: