2-x+1/x-2-x-4/x+2 can be written as a single fraction in the form ax+b/x^2-4 where a and b are integers

work out the value of and and the value of b

Express as a single fraction in its simplest form as a single fraction in its simplest form 

3/(x+1) – 1/(x-2) 

the answer is 2x-7/(x+1)(x-2) 

To simplify into 1 fraction, remember, we must make the denominator the same
x/ (x-1 )  - 1/ (2-2x)
= -x/ -(1-x) - 1/(2-2x)    [see the similarity now? ]  [whatever we multiply for the denominator, as long as we multiply to the numerator, it will be ok]
= -2x / -(2-2x)    + 1/-(2-2x)
= (-2x+1 )/ -(2-2x)
=(2x-1)/(2-2x)