GRE Math : How to add rational expressions with a common denominator

Study concepts, example questions & explanations for GRE Math

varsity tutors app store varsity tutors android store varsity tutors amazon store varsity tutors ibooks store

Example Questions

Example Question #1 : Expressions

Simplify the following rational expression: (9x - 2)/(x2) MINUS (6x - 8)/(x2)

Possible Answers:

Correct answer:

Explanation:

Since both expressions have a common denominator, x2, we can just recopy the denominator and focus on the numerators. We get (9x - 2) - (6x - 8). We must distribute the negative sign over the 6x - 8 expression which gives us 9x - 2 - 6x + 8 ( -2 minus a -8 gives a +6 since a negative and negative make a positive). The numerator is therefore 3x + 6.

Example Question #6 : Rational Expressions

Simplify the following rational expression:

 

Possible Answers:

Correct answer:

Explanation:

Since both fractions in the expression have a common denominator of , we can combine like terms into a single numerator over the denominator:

Example Question #7 : Rational Expressions

Simplify the following expression:

Possible Answers:

Correct answer:

Explanation:

Since both terms in the expression have the common denominator , combine the fractions and simplify the numerators:

Example Question #8 : Rational Expressions

Simplify the following rational expression:

Possible Answers:

Correct answer:

Explanation:

Since both rational terms in the expression have the common denominator , combine the numerators and simplify like terms:

 

Example Question #1 : How To Add Rational Expressions With A Common Denominator

Add and simplify:

Possible Answers:

Correct answer:

Explanation:

When adding rational expressions with common denominators, you simply need to add the like terms in the numerator.  

Therefore,  is the best answer. 

Tired of practice problems?

Try live online GRE prep today.

1-on-1 Tutoring
Live Online Class
1-on-1 + Class
Learning Tools by Varsity Tutors