All PSAT Math Resources
Example Question #1 : Rational Expressions
Same denominator means you add straight across the numerators, keeping the denominator the same.
Add like terms.
Example Question #2 : Rational Expressions
Check for same Denominator
Add like terms
Check for GCF or if the expression can be factored
After factoring, divide out like terms.
Example Question #1 : How To Add Rational Expressions With A Common Denominator
Simplify the following rational expression: (9x - 2)/(x2) MINUS (6x - 8)/(x2)
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.