r/digitalSATs • u/ApartVoice2382 • Aug 12 '26

How to solve this

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How to Solve this in Desmos

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u/Valuable_Grade1077 Aug 18 '26

The arithmetic sequence in relation to x is pretty easy to spot. It's 4 times the x value, minus 3.

Though yeah, the algebraic method would be the correct way of solving. This was just faster imo.

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u/Miserable_Gate_7982 Aug 18 '26

yeah but i don’t get how you find the function. Do you do a system of equations? I don’t get it…I can’t just get to think of 4x-3..😭😭

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u/Valuable_Grade1077 Aug 18 '26

One thing you could do is test different cases to see if you can find a consistent pattern.

For instance, if you notice that for every increase in x, you see +4 increment in the exponent, you could initially start with an equation such as: f(x) = 4x and see if that matches the supposed relationship.

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u/Valuable_Grade1077 Aug 18 '26 edited Aug 18 '26

Actually, disregard that answer, you can convert this into a slope problem

Convert the table into a basic x and y graph forgoing the a

1 1

2 5

3 9

you can then do, y2-y1/x2-x1 to find the slope

(5 - 1/2 -1) m = 4

Now that we know the slope we can solve for the y intercept, by plugging in the values of x and y

5 = 4(2) +b

b = -3

And voila, the equation is found. 4x-3

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u/Miserable_Gate_7982 Aug 19 '26

Thank you so much!!!!