Standard deviation=4.
let the mean be 12 and the score be 0 (therefore 12 point difference.)
0-12/s=-3 (s being standard deviation)
-12/4 = -3
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Equation Given :
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16x² = 121
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Take away 121 from both sides:
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16x² - 121 = 0
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Make each term a perfect square
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(4x)² - (11)² = 0
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Apply algebraic rule : a² - b² = (a + b)(a - b)
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(4x + 11) (4x - 11) = 0
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Apply zero product property :
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4x + 11 = 0 or 4x - 11 = 0
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Solve for x :
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4x = - 11 or 4x = 11
x = -11/4 or x =11/4
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Answer: x = -11/4 or x = 11/4
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Density graphs have an area of 1 to represent 100% of the possibilities.
The length is 80
80 * height = 1
Height = 1 / 80
Height = 0.0125 (D)
Answer:

Step-by-step explanation:
The given system of equations is presented as follows;

3·t - 6·s = 9
Making <em>t</em> the subject of both equations, gives;
In the first equation; t = (3 - s/2)/5
In the second equation; t = (9 + 6·s)/3
Equating both values of <em>t</em> to find the the values that satisfies both equations, gives;
(3 - s/2)/5 = (9 + 6·s)/3
3 × (3 - s/2) = 5 × (9 + 6·s)
9 - (3/2)·s = 45 + 30·s
45 - 9 = (30 + (3/2))·s
36 = (63/2)·s
s = 36/(63/2) = 8/7
t = (3 - s/2)/5
∴ t = (3 - (8/7)/2)/5 = 17/35
Therefore, the ordered pair is (8/7, 17/35)