Divide Rational Expressions
How to divide rational expressions: 2 examples and their solutions.
Examplex/(3x - 1) ÷ (x + 7)/2x
Solution
Solution (Detail)
To solve the division sign [ ÷ ],
change [ ÷ ] to [ ⋅ ],
and switch the numerator and the denominator
of the fraction right behind [ ÷ ]:
(x + 7)/2x → 2x/(x + 7).
x⋅2x = 2x2
(3x - 1)⋅(x + 7) = (3x - 1)(x + 7)
So
2x2/(3x - 1)(x + 7)
is the answer.
Example(x2 - 4)/(x - 1) ÷ (x + 2)/5
Solution
Solution (Detail)
Factor the numerator
x2 - 4.
x2 - 4
= (x + 2)(x - 2)
Factor the Difference of Two Squares: a2 - b2
x2 - 4
= (x + 2)(x - 2)
So (given) = (x + 2)(x - 2)/(x - 1) ÷ (x + 2)/5.
Change [ ÷ ] to [ ⋅ ],
and switch the numerator and the denominator
of the fraction right behind [ ÷ ]:
(x + 2)/5 → 5/(x + 2).
Cancel the common factor (x + 2).
Then 5(x - 2)/(x - 1).
Simplify a Rational Expression
So
5(x - 2)/(x - 1)
is the answer.