How do I find the derivative of: y = 2/(2-x)

I know that I will have to take the limit of "(f(x+h) - f(x))/h" as h approaches 0, but the algebra is really confusing me. If anyone could help, that would be much appreciated. Thanks in advance!

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- Jun 17th 2013, 10:39 AMmisiaizeskaFinding derivative by first principles?
How do I find the derivative of: y = 2/(2-x)

I know that I will have to take the limit of "(f(x+h) - f(x))/h" as h approaches 0, but the algebra is really confusing me. If anyone could help, that would be much appreciated. Thanks in advance! - Jun 17th 2013, 10:46 AMHallsofIvyRe: Finding derivative by first principles?
You know that so it should be easy to see that .

Now . You need to get "common denominators" by multiplying both numerator and denominator of the first fraction by 2- x and numerator and denominator of the second fraction by 2- x- h:

Can you finish that?