# Math Help - Rational functions question

1. ## Rational functions question

A rational function y= a/(x-7) +k passes through the points (10,1) and (2,9) find values of a and k.

How do i do this, i know how to find one of any value, a,h,k but not two

2. ## Re: Rational functions question

Where did h come from? Your function is \displaystyle \begin{align*} y = \frac{a}{x - 7} + k \end{align*}, so there are only two parameters, a and k.

By substituting each of the two points into the equation, you will get two equations with a and k as unknowns. Solve them simultaneously.

3. ## Re: Rational functions question

how do i substitute both of them at the same time?

if 1=a/(10-7) + k

how do i find both?

4. ## Re: Rational functions question

You don't. Substitute one point to give you the first equation, which you have done.

Then go back to the original equation and substitute the second point to give you the second equation.

5. ## Re: Rational functions question

i dont understand how can i just ignore one unknown value?

6. ## Re: Rational functions question

i got it thanks