Hi,
these are all info i have.

x 3 5 8 6 9
y 1 5.5 6 7 2.5
A polynomial made this text
So find it out and solve for x

can somebody help me please

regards
helmut

Start by assuming its a quadratic:

y=ax^2+bx+c

Sort the data points into scending order for x.

Put the values for the first third and fifth data points into this which will give you a set of three simultaneous equations for this, which you can solve for a,b and c.

Alternativly look up quadratic regression on Google.

If you don't want a quadratic fit you can repeat the first method for a cubic or quartic.

It would also help if you provided more background information on the source of this question.

CB