Pd 3A Adding and Subtracting Rational Expressions

Adding and Subtracting Rational Expressions

Open Ended

Do Now: Add/subtract the following rational numbers.

$$\frac{a}{m}+\frac{b}{2m}-\frac{c}{m}$$  

Adding/Subtracting Rational Expressions

• Exact same procedure as adding/subtracting fractions

• Must have a common denominator!

• Once you have a common denominator, you add/subtract the numerators

Multiple Choice

Try on your own: Add the following expressions. Simplify Completely

• $$\frac{x-3}{5\left(x-8\right)}$$  

• $$\frac{3x-3}{x^2-2x-20}$$  

• $$\frac{x^2+2x-15}{5\left(x+5\right)\left(x-8\right)}$$  

• Can't add these

Subtracting Rational Expressions!

• Same as adding rational expressions, but one extra thing!

• DISTRIBUTE THE NEGATIVE ALL THE WAY THROUGH

Multiple Choice

Try on your own: Subtract the following expressions. Simplify completely.

• $$\frac{x^2+4x-12}{\left(x-2\right)\left(x+2\right)\left(x+10\right)}$$

• $$\frac{x+6}{\left(x+2\right)\left(x+10\right)}$$

• $$\frac{x-6}{8x-24}$$

• Can't subtract these

Multiple Select

What do you have to do when adding or subtracting rational expressions? Check all that apply.

• Find a common denominator

• Solve for x

• Simplify completely

• Nothing

• Distribute the negative (Subtracting only)

Poll

How confident are you with adding/subtracting rational expressions?