ACT Preparation / Unit 8 ACT 0715 short lesson, about 20 seconds
Cancel Factors, Not Terms
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The idea
A rational expression is simplified by factoring the numerator and denominator and cancelling common factors. Only factors cancel, never terms joined by addition or subtraction.
In practice
(x² − 9)/(x + 3) = (x + 3)(x − 3)/(x + 3) = x − 3.
Where people slip
(x + 2)/(x + 5) does not reduce: the x's are terms, not factors.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
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