The general equation of a circle is
(x-a) ^ 2 + (y-b) ^ 2 = r ^ 2
for this case the values of a and b are
a = 2
b = 0
The radius of the circle is
r ^ 2 = 14
r = (14) ^ (1/2) = 3.74
12.75
PROOF:
find all the m's first
3m+3m+m+m=8m
8m=102
Divide both sides, and you get
12.75
Our matrix C is the encoder. Let X be our secret message and let B be our encoded message. Therefore the relationship between the 3 can be represented as:
CX = B
So we want to solve for X (our secret message). So using matrix algebra:
X = C^-1*B
where C^-1 is the inverse of C.
C^-1 = | 3 -2 |
|4 -3 |
So we take C^-1 and multiply it by matrix B to get X. Matrix B is already given to us. So just multiply those two. I used a calculator to get:
X = | 20 8 5 3 15 12 15 |
| 18 9 19 2 12 21 5 |
And since A = 1, B = 2, C = 3, etc....
We decode our message and it says:
X = | T H E C O L O |
| R I S B L U E |
So the answer is: The color is blue (D)
The fact that the coefficients are pairwise identical (except for sign) tells you that x^2 -1 is a factor (and x-5 is the other factor). Of course, you recognize x^2-1 as a special form (the difference of squares) that is factored as (x +1)(x -1).
The zeros are x = -1, +1, +5.
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A graphing calculator confirms this.
The new width is 16.6666666667 inches, which can be rounded to 16.7.
Width: 5 ?
Height: 6 20
We know that based on the information provided, the new height is 20 inches.
So, in order to solve, you can cross multiply (5 x 20), which would be 100. Then
divide by 6, to get 16.6666666667 or 16.7.
