Rational expressions and restrictions
Equivalent expressions · Stage 3
Recognize the pattern
Factor before canceling, and retain exclusions from the original denominator.
Useful ruleDenominator ≠ 0
Build on: ADM-02
Try it before reading the solution
Simplify (x² − 9)/(x − 3). State any restriction.
This teaching example is original and is not an official SAT question.
Reasoning
Factor the numerator as (x−3)(x+3); cancel only when x≠3.
Answerx + 3, with x ≠ 3
03 · Next step
See membership →Ready for adaptive practice
Practice questions remain in English, as on the SAT.