Answer:

Step-by-step explanation:

Ways to spot if an expression is not a polynomial:
1) If there is a negative exponent
2) If there is division by a variable
3) If the power is something other than a non-negative integer
If any of these conditions exist, the expression will not be a polynomial. Now consider the options. Option A has negative exponent, Option B involves division by a variable and Option D has a exponent which is not a number.
So, from the given options, option C is the only polynomial
We have the following data:
Margin of Error = E = 2.7 % = 0.027
Sample size = n = 900
Proportion of adults in favor = p = 60% = 0.6
We need to find the confidence level. For this first we need to find the z value.
The margin of error for a population proportion is given as:

Using the values, we get:
As, seen from the z table, z=1.65 corresponds to the confidence level 90%. So, the answer to this question is option B
The midpoint is C, (-0.5,0.5)
Find the middle between the x and y coordinates and that is the midpoint
Answer:
C. x+y = 1 and -x-y = -1
Step-by-step explanation:
Remember that if a system of equations has an infinite number of solutions, then the resulting equation from using the first step of the elimination method would have no variables and would be true.
1) Let's try canceling out the equations in option C, x+y =-1 and -x-y =-1. Add the two equations together. (Work shown in attached picture.)
2) All of the terms cancel out with each other, leaving only a true statement of 0 = 0. Thus, option C is the answer.