9514 1404 393
Answer:
- 6x +y = -6
- 6x -y = 8
- 5x +y = 13
Step-by-step explanation:
To rewrite these equations from point-slope form to standard form, you can do the following:
- eliminate parentheses
- subtract the x-term
- subtract the constant on the left
- if the coefficient of x is negative, multiply by -1
Of course, any operation you do must be done <em>to both sides of the equation</em>.
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1. y -6 = -6(x +2)
y -6 = -6x -12 . . . . . eliminate parentheses
6x +y -6 = -12 . . . . . add 6x
6x +y = -6 . . . . . . . . add 6
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2. y +2 = 6(x -1)
y +2 = 6x -6
-6x +y +2 = -6
-6x +y = -8
6x -y = 8 . . . . . . . . multiply by -1
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3. y -3 = -5(x -2)
y -3 = -5x +10
5x +y -3 = 10
5x +y = 13
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<em>Additional comment</em>
The "standard form" of a linear equation is ax+by=c for integers a, b, c. The leading coefficient (generally, 'a') should be positive, and all coefficients should be mutually prime (have no common factors). That is why we multiply by -1 in problem 2.
3 odd integers have a property that they average up to the middle large one. Let's say we have 3, 5, and 7. 3 is 2 less than 5 and 7 is 2 more than 5. so when you add them it equals 2 times 5.
After we know that, the sum of 3 odd integers is just 3 times the middle number. ex. 3+5+7 = 3 times 5 = 15
Then we know the some number times three = 225. we find out that the middle number is 75, so the other two are 73 and 77
Supposing, for the sake of illustration, that the mean is 31.2 and the std. dev. is 1.9.
This probability can be calculated by finding z-scores and their corresponding areas under the std. normal curve.
34 in - 31.2 in
The area under this curve to the left of z = -------------------- = 1.47 (for 34 in)
1.9
32 in - 31.2 in
and that to the left of 32 in is z = ---------------------- = 0.421
1.9
Know how to use a table of z-scores to find these two areas? If not, let me know and I'll go over that with you.
My TI-83 calculator provided the following result:
normalcdf(32, 34, 31.2, 1.9) = 0.267 (answer to this sample problem)
B.
as a, none is longer than 11 inches
b, 2 are longer than 11 inches
c, 3 have 9 inches (which is the shortest)
s, one has 9 inches
