If z varies jointly with x and y, x = 2 and y = 2, z = 7. Find z when x = 4 and y = 8.
1 answer:
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Answer:
(x, y) = (3, 5)
Step-by-step explanation:
To solve these equations graphically, you plot each one, then identify the coordinates of the point of intersection.
The first equation can be graphed using the y-intercept of -1 and the slope of 2.
The second equation has a y-intercept of 18/3 = 6, and a slope of -1/3. The x-intercept of 18 is off the chart, so the slope and intercept are a good way to plot this line, too.
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The slope is the "rise" divided by the "run". A slope of 2 means the line goes up 2 units for each unit to the right. A slope of -1/3 means the line goes down 1 unit for each 3 units to the right.
The solution is (x, y) = (3, 5).
