3 and 6- solve by graphing other two solve by substitution
1 answer:
Answer:
3. (x, y) = (3, 2)
6. (x, y) = (10, 4/3)
9. (x, y) = (-2, -1)
12. (x, y) = (8, 3)
Step-by-step explanation:
3, 6. See the attachment. 3 is graphed in red/orange. 6 is graphed in blue, purple.
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9. Use the expression for y in the second equation to substitute for y in the first equation:
4(3x +5) -x = -2
12x +20 -x = -2 . . . eliminate parentheses
11x = -22 . . . . . . . . subtract 20, collect terms
x = -2 . . . . . . . . . . . divide by 11
y = 3(-2) +5 = -1 . . .substitute for x in the second equation
The solution is (x, y) = (-2, -1).
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12. Subtract 3/4x from the second equation to get an expression for y:
y = 9 - 3/4x
Substitute that into the first equation:
3(9 -3/4x) -5/4x = -1
27 -9/4x -5/4x = -1 . . . . eliminate parentheses
-14/4x = -28 . . . . . . . . . . collect terms, subtract 27
x = 8 . . . . . . . . . . . . . . . . multiply by -4/14
y = 9 -3/4(8) = 3 . . . . . . substitute into the expression for y
The solution is (x, y) = (8, 3).
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Using the z-distribution, it is found that the lower limit of the 95% confidence interval is of $99,002.
<h3>What is a z-distribution confidence interval?</h3>The confidence interval is:
In which:
is the sample mean.
- z is the critical value.
- n is the sample size.
is the standard deviation for the population.
In this problem, we have a 95% confidence level, hence, z is the value of Z that has a p-value of
, so the critical value is z = 1.96.
The other parameters are given as follows:
Hence, the lower bound of the interval is:
The lower limit of the 95% confidence interval is of $99,002.
More can be learned about the z-distribution at brainly.com/question/25890103
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