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When adding or subtracting algebraic fractions, the first thing to do is to put them onto a common denominator (by cross multiplying).
e.g. 1 + 4
(x + 1) (x + 6)
= 1(x + 6) + 4(x + 1)
(x + 1)(x + 6)
= x + 6 + 4x + 4
(x + 1)(x + 6)
= 5x + 10
(x + 1)(x + 6)
Solving equations
When solving equations containing algebraic fractions, first multiply both sides by a number/expression which removes the fractions.
Example:
Solve 10 – 2 = 1
(x + 3) x
multiply both sides by x(x + 3):
\ 10x(x + 3) – 2x(x + 3) = x(x + 3)
(x + 3) x
\ 10x – 2(x + 3) = x² + 3x [after cancelling)
\ 10x – 2x – 6 = x² + 3x
\ x² – 5x + 6 = 0
\ (x – 3)(x – 2) = 0
\ either x = 3 or x = 2