posted by jazmin on .
can you answer this please about sums and differences of a rational algebraic expression this is the problem 5/x-7 - x-1/x-7 - 2+x/x-7 another is x+1/2 - x-2/3 + 2x-1/9 another is 2x+3/3 - 3x-1/2 + x-4/12
did you mean
5/(x-7) - (x-1)/(x-7) - (2+x)/(x-7)
since you already have a common denominator, just add/subtract the numerators
= (5 - x + 1 - 2 - x)/(x-7)
for the second, your common denominator would be the LCM of 2,3, and 9 which would be 18
(x+1)/2 - (x-2)/3 + (2x-1)/9
= [9(x+1) - 6(x-2) + 2x-1 ] /9
third one is just as easy, the LCD is 12
obviously I have a typo in the second question, should say ...
(x+1)/2 - (x-2)/3 + (2x-1)/18
= [9(x+1) - 6(x-2) + 2x-1 ] /18