Answer:
Step-by-step explanation:
we know that
Applying the law of cosines
we have
substitute
Work only with the second equation at the beginning. Solve for x for it.
7x - 2x = 3 Combine the left hand side.
5x = 3 Divide by 5
5x/5 = 3/5 Do the division
x = 3/5 = 0.6
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Now work with the top equation.
3(0.6) + 5y = 13 Multiply on the left.
1.8 + 5y = 13 Subtract 1.8 from both sides.
1.8 - 1.8 + 5y = 13 - 1.8 Do the subtraction
5y = 11.2 Divide by 5
5y/5 = 11.2/5
y = 2.24 Answer
Based on the given variation, y does not vary directly with x and the constant of variation are 8, 3.2 and 1.25 respectively.
<h3>Variation</h3>
y = k × x
where,
k = constant of proportionality
y = -40
x = -5
y = k × x
-40 = k × -5
-40 = -5k
k = -40/-5
k = 8
when,
y = 8 and x = 2.5
y = k × x
8 = k × 2.5
8 = 2.5k
k = 8/2.5
k = 3.2
when,
y = 5 and x = 4
y = k × x
5 = k × 4
5 = 4k
k = 5/4
k = 1.25
Learn more about variation:
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Answer:
C) a positive correlation
Step-by-step explanation:
<em>More people ⇒ Longer time</em> is a positive correlation between those variables. However, <em>longer time</em> is not the desired outcome.
Rather, <em>shorter time</em> is the desired outcome. The correlation between <em>more people</em> and <em>shorter time</em> is negative. In order to compute that correlation numerically, one would have to define a function that would give a numerical value for "shorter time" that would model the goodness of outcome as time gets shorter.
