can someone EXPLAIN this to me? you don't have to answer the questions. They are for my college class. Last assignment! thank you..

Your questions are rational expressions.

Essentially, you are adding/subtracting fractions with unknown values (i.e. the variable x).

If you want to add/subtract these, you need a common denominator. Just like you find a CD in 1/2 + 1/3, you have to find a CD between x^2 + x and x (question 20).

Rearranging gives us x(x + 1) and x. Now to find a common denominator, we multiply both the denominator by (x + 1), so now our denominators are both x(x+1) (common). Except that if we multiply on the denominator, we must also multiply on the numerator.

After doing these steps, you can finally add the numerator. Same concept with subtraction.

I hope this helps!

3x+9+4x+x=8x+9that's the answer for your question.