16x + 9 = 9y-2x Add 2x to both sides
18x + 9 = 9y Divide both sides by 9
2x + 1 = y Switch the sides to make it easier to read
y = 2x + 1
Answer:
C. 
Step-by-step explanation:
Given:

Add the two equations, we get

Therefore, the correct option is option C.
Answer:
(x - 3)^2 + (y + 1) = 25
Step-by-step explanation:
First find the midpoint of the diameter, because that represents the center of the circle.
-1 + 7
The x-coordinate of the midpoint is xm = ---------- = 3
2
2 - 4
and the y-coordinate is ym = ---------- = -1
2
And so the center of this circle is at (3, -1).
Use the Pythagorean Theorem to determine the square of the radius:
square of radius = 4^2 + (-3)^2 = 16 + 9 = 25
And so the equation of this circle is (x - 3)^2 + (y + 1) = 25
The equation for standard deviation is finding the mean of the numbers, subtracting each of the initial numbers by the mean, squaring each of the results, finding the mean of these results added together, then finding out the square root of the results added together.
The mean of 175 and 165 is 170, subtract 175 and 165 by 170, and you get 5 and -5 respectively. Then, square the results and you get 25 and 25.
Add the two numbers together (25 & 25) then find the square root of it, which is <span>7.07106781187, simplified to 7.07.</span>