Monday, January 7, 2013

How do we add and subtract rational expressions?

When adding and subtracting rational expressions you need to get the same denominator. For example if your problem is 2/x+1 + 9/x-1. You would multiply the first fraction by x-1 top and bottom. What ever you do to the denominator you MUST do to the numerator. That fraction now becomes 2x-2/x^2-1. The second fraction you would multiply the top and bottom by x+1. That now becomes 9x+9/x^2-1. Now that they share the same denominator you can began solving. You now have 2x-2 + 9x+9/x^2-1. The 2x+9x becomes 11x and -2+9 equals 7. Your final answer is 11x+7/x^2-1.

No comments:

Post a Comment