MATH LESSON
SIMPLIFYING: RATIONAL EXPRESSIONS
A rational expression is a fraction where the numerator and denominator are polynomials. Simplify it like a regular fraction!
To simplify a rational algebraic expression, factor both the numerator and denominator, then divide out (cancel) any common factors.
P(x)Q(x) = Factored P(x)Factored Q(x) = Simplified Form
x² - 9x + 3
=
(x - 3)(x + 3)x + 3
=
x - 3
What is a Rational Algebraic Expression?
It is a ratio of two polynomials. The denominator cannot be zero.
The "Factor and Cancel" Method
Look at 45x63x4. Divide coefficients (45 ÷ 3 = 15) and subtract exponents (x6-4 = x2). Result: 15x²
Common Mistakes!
Mistake: Forgetting to factor first before canceling.
x² - 9x + 3 = x - 93 × WRONG
x² - 9x + 3 = (x-3)(x+3)x+3 = x - 3 ✓ CORRECT
Worked Examples
Example 1: Simplify: 45x63x4
→ 15x²
→ 15x²
Example 2: Simplify: x² - 9x + 3
→ x - 3
→ x - 3
MATH SEATWORK
Seatwork Time!
Answer all 5 questions. Good luck!
Please select an answer first!
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Made for students who want to master Simplifying Rational Algebraic Expressions