Answers:
- The direct variation equation is y = 5x
- If x = 4, then y = 20
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Explanation:
Let's say that the letter k replaces the green box
We have the equation y = kx
Plug in (x,y) = (7,35) to get the equation 35 = k*7
Dividing both sides by 7 leads to k = 5
Therefore, the direct variation equation is y = 5x
We can check this by plugging in x = 7
y = 5x
y = 5*7
y = 35
So x = 7 leads to y = 35 as expected.
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Do the same for x = 4
y = 5x
y = 5*4
y = 20 when x = 4
Side note: direct variation equations always go through the origin.