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3 years ago

Solve the equation with substitution 3x-2y=9 Y=2x-7

1 answer:

3 0

$3x-2y=9 \\
y=2x-7 \\ \\
\hbox{substitute 2x-7 for y in the 1st equation:} \\
3x-2(2x-7)=9 \\
3x-4x+14=9 \\
-x+14=9 \ \ \ |-14 \\
-x=-5 \ \ \ |\times (-1) \\
x=5 \\ \\
y=2x-7=2 \times 5-7=10-7=3 \\ \\
\boxed{(x,y)=(5,3)}$

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Answer:

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So the correct answer would be:

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Step-by-step explanation:

Previous concepts

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

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The confidence interval would be given by this formula

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$0.7 + 2.58 \sqrt{\frac{0.7(1-0.7)}{500}}=0.753$

And the 99% confidence interval would be given (0.647;0.753).

So the correct answer would be:

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