Quadratic Equation: x^-2-9x^-1+18=0

[mbrown97]

I am having trouble with quadratic equation with negative exponents in it. The problem is:

x^-2-9x^-1+18=0. How do I begin. Any help is appreciated.

 

[mark07]

\(\displaystyle \L x^{-2} - 9x^{-1} +18 =0\)

\(\displaystyle \L \frac{1}{x^2} - \frac{9}{x} +18 =0\)

Multiply both sides by x^2,

\(\displaystyle \L 18x^2 -9x +1 =0\)

Can you finish now?

 

[tkhunny]

You may wish to remember that you have changed the Domain by this transformation. Be sure to check your answers before you think you are done.