Quadratic sequence

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Jasonrich

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Hi, I'm kinda stumped on this question. I've tried multiple things and I just keep doing something wrong :confused:

I'm given the quadratic sequence: 6; x^2 + 2; 6x + 2; 11x
I need to solve for x

I know this isn't that difficult but I'm at a loss :(

Any help will be much appreciated :)
 
You want the secondary differences to be constant. Can you find the three primary differences?
 
Second expression minus the first, third expression minus the second, fourth expression minus the third.

Now, find the two differences for these three primary differences (these are the secondary differences), equate them and solve for x.
 
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MarkFL said:
Second express minus the first, third expression minus the second, fourth expression minus the third.

Now, find the two differences for these three primary differences (these are the secondary differences), equate them and solve for x.
Click to expand...

So then it would be: 6; x^2 + 2; 6x + 2; 11x
x^2 - 4; -x^2 + 6x; 5x - 2
-2x^2 + 6x + 4; x^2 - x - 2

​I may be wrong?

and then: -2x^2 + 6x + 4 = x^2 - x - 2 ​?

Please tell me if I did anything wrong, I've never quite grasped the concept of number patterns :confused:
 
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That's what I get, so move everything to one side to get the equation in standard quadratic form, and you will find it factors nicely.
 
I'm given the quadratic sequence: 6; x^2 + 2; 6x + 2; 11x
I need to solve for x

Seq: 6; x^2 + 2; 6x + 2; 11x

Diff 1: x^2 -4; 6x-x^2 ; 5x - 2;
Diff 2: 4+6x-2x^2; -2-x+x^2
Diff 3: -6-7x+3xx = 0


 
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