An algebraic fraction is a fraction that has variables (letters) in the numerator, denominator, or both.
Examples:
x / 5, 3x+2 / 7, 2x / x+4, x^2−1 / x
Just like regular fractions, algebraic fractions represent division.
So:
2x / x+4 = “2x÷(x+4)”
⭐ Parts of an Algebraic Fraction
Example:
3x+1 / x−2
-
Numerator (top):
-
Denominator (bottom):
📌 Important rule: The denominator can never be 0
So for this fraction:
x−2≠0⇒x≠2
That’s called a restriction (or “excluded value”).
✅ Simplifying Algebraic Fractions
Simplifying algebraic fractions is like simplifying regular fractions:
Key rule:
You can only cancel factors, not terms.
✅ Canceling factors (allowed)
6x / 3 = 2x
❌ Canceling terms (not allowed)
x+2 / x ≠ 2 / 1
You cannot cancel the x across addition.
🔥 Example: Simplify
6x / 9
Divide top and bottom by 3:
2x / 3
🔥 Example with factoring
x2−9 / x+3
Step 1: Factor the numerator:
x^2 – 9 = (x-3)(x+3)
Now:
(x−3)(x+3) / x+3
Cancel the common factor :
✅ Simplified result:
📌 BUT restriction still matters:
x≠−3x
Even though it cancels, the original fraction would be undefined at x = -3
✅ Multiplying Algebraic Fractions
Multiply straight across:
a / b ⋅ c / d = ac / bd
Example:
2x / 3 ⋅ 9 / x = 18x / 3x
Cancel:
(Restriction: x≠0)
✅ Dividing Algebraic Fractions
Dividing means multiply by the reciprocal:
a / b ÷ c / d = a / b ⋅ d / c
Example:
x / 4 ÷ 2 / x = x / 4 ⋅ x / 2 = x^2 / 8
(Restriction: x ≠ 0)
✅ Adding/Subtracting Algebraic Fractions (Hardest Part)
Just like regular fractions, you need a common denominator.
Example:
1 / x + 2 / x = 3 / x
Easy because denominators match.
Example with different denominators:
1 / x + 1 / x+1
Common denominator:
Rewrite:
x+1 / x(x+1) + x / x(x+1)
Add:
2x+1 / x(x+1)