Functions (MCR3U) · Characteristics of Functions

Inverse of a linear function

Find the inverse of a linear function f(x) = mx + b. Unlimited questions, five difficulty levels, and a full worked solution every time — free.

Practice this skill Curriculum: MCR3U-CF1.4

Try one

Find the inverse of the function.

f(x) = 3x + 5
  • (x - 5)·3
  • (x - 5)/3
  • (x + 5)/3
  • (x - 3)/5

Answer: (x - 5)/3

See one solved, step by step

Find the inverse of the function.

f(x) = 2x + 6
  • (x - 2)/6
  • (x - 6)/2
  • (x - 6)·2
  • (x + 6)/2
📘 Worked solution
1y = 2x + 6Write the function as y = f(x).
2x = 2y + 6Swap x and y — this is the key step for finding an inverse.
3x - 6 = 2yMove 6 to the other side to isolate the y-term.
4f-1(x) = (x - 6)/2Divide both sides by 2 to solve for y.

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