Functions (MCR3U) · Characteristics of Functions

Simplify rational expressions

Factor and simplify a rational expression by cancelling a common binomial factor. Unlimited questions, five difficulty levels, and a full worked solution every time, included free with weekly lessons.

Practice this skill Curriculum: MCR3U-CF3.1

Try one

Simplify the rational expression.

(x2 + 3x - 10) / (x2 + 8x + 15)
  • (x + 2)/(x - 3)
  • (x - 2)/(x + 5)
  • (x + 5)/(x + 3)
  • (x - 2)/(x + 3)

Answer: (x - 2)/(x + 3)

See one solved, step by step

Simplify the rational expression.

(x2 + x - 12) / (x2 - 9)
  • (x + 4)/(x - 3)
  • (x + 4)/(x + 3)
  • (x - 4)/(x - 3)
  • (x - 3)/(x + 3)
📘 Worked solution
1Numerator: x2 + 1x - 12 = (x - 3)(x + 4)Find two numbers that multiply to -12 and add to 1: -3 and 4.
2Denominator: x2 + 0x - 9 = (x - 3)(x + 3)Find two numbers that multiply to -9 and add to 0: -3 and 3.
3(x - 3)(x + 4) / [(x - 3)(x + 3)] = (x + 4)/(x + 3)(x - 3) appears in both the top and bottom, so divide it out (x cannot equal 3).

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