SOLUTION: what is the function rule for the graph: x y 1 20 2 16 3 12 4 8 ?

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Question 536572: what is the function rule for the graph:
x y
1 20
2 16
3 12
4 8
?
Answer by jim_thompson5910(35256) (Show Source):
You can put this solution on YOUR website!
As x increases by 1 each time, y decreases by 4 each time.

So the slope is -4/1 = -4, telling us that m = -4

So the equation y = mx+b then becomes y = -4x+b

Now, when x = 1, y = 20. Plug this in to get 20 = -4(1)+b

and solve for b to get: b = 24

So the equation that models the data is

This is a linear equation.

Note: alternatively, you can replace 'y' with f(x) to get

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Jim