Question

Using the Gauss-Jordan method need to determine the coefficients a,b,c of the quadratic equation
x=ax squared +bx+c y=5.4 and x=8

Answer 1

Don't you mean

y = ax^2 +bx + c ?

You would need three (x,y) pairs to determine three coefficients. You only provided one.

The Gauss-Jordan method applies to matrices of more than one linear equation. You have one quadratic equation.

I (or the question) must be missing something, but I don't see it.

Answer 2

Here are the three equations
x=8, x=13, x=18 y=5.4, y=6.3, y=5.6

Answer 3

Yes I do mean y = ax^2 +bx + c

Answer 4

<<Here are the three equations
x=8, x=13, x=18 y=5.4, y=6.3, y=5.6
>>

Those are not three equations. They are possibly the coordinates of three points, arranged in a confusing manner.
(x,y) = (8,5.4), (13,6.3) and (5.5,5.6)

With those points, and the Gauss-Jordan method, it is possible to calculate the values of a, b, and c for a parabolic (quadratic) curve
y = ax^2 + bx +c gthat goes through through those points. You would be solving these 3 equations:
64a + 8b + c = 5.4
169a + 13b + c = 6.3
30.25a + 5.5b + c = 5.6
The next step is to evalauate four determinants. One of them is
|64 8 1|
|169 13 1|
|30.25 5.5 1|

That is as far as I am going to go with this.

Answer 5

I can solve from here. My problem is I cannot pick out the data and put it in the right order. Any suggestions.