Add and Subtract Rational Expressions with Unlike Denominators: example 8.41

Add: $\frac{5}{12 x^{2} y} + \frac{4}{21 x y^{2}} .$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Add: $\frac{2}{15 a^{2} b} + \frac{5}{6 a b^{2}} .$

How did it go?


Find the LCD of $12 x^{2} y$ and $21 x y^{2}$ .

Rewrite each rational expression as an equivalent fraction with the LCD.
Simplify.
Add the rational expressions.
There are no factors common to the numerator and denominator. The fraction cannot be simplified.


Find the LCD of $12 x^{2} y$ and $21 x y^{2}$ .

Rewrite each rational expression as an equivalent fraction with the LCD.
Simplify.
Add the rational expressions.
There are no factors common to the numerator and denominator. The fraction cannot be simplified.