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hi im not sure how to find the rule for a function table

x=1, 2, 3, 4

y=9,27,45,63

Y=?x-?

that is the linear equation but i don't know how to fill in the question marks

Hi Brittany,

Since the relationship is linear, you can take any two sets of points to model the linear line

y = mx + c

where m = Δy/Δx

If we take x=1,y=9 and x=2,y=27

m = (27 - 9)/(2 - 1)

= 18

So,

y = 18x + c

and you can find c using any of the points, say, x=1,y=9

9 = 18(1) + c

9 = 18 + c

c = -9

Therefore,

y = 18x - 9

Another way to do this is to consider the y sequence as a linear progression with first term 9 and common difference 18, and so

y = 9 + (x-1).18

= 9 + (18x - 18)

= 18x - 9

Regards

Advanced Math

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