2.13B

Exponential and Logarithmic Equations and Inequalities

about 30 min · 6 short parts · stop after any part
Questions like *"when will my money reach at least $10,000?"* are inequalities with exponents or logs.
By the end you can solve them, and you can undo (invert) any exp or log function.

The path

  1. 1
    Warm-up: the tools you need
    You can switch log ↔ exponent, find where a log exists, and combine logs.
  2. 2
    Exponential inequalities (nice powers)
    You can solve 3x+2−4>233^{x+2} - 4 > 23.
  3. 3
    When the power isn't nice
    You can solve 3x<503^x < 50 and money problems with A=PertA = Pe^{rt}.
  4. 4
    Log inequalities: one log
    You can solve log⁡2(2x+6)>3\log_2(2x+6) > 3, domain included.
  5. 5
    Log inequalities: logs on both sides
    You can solve log⁡(x−8)+log⁡2≤log⁡(3x+4)\log(x-8) + \log 2 \le \log(3x+4).
  6. 6
    Inverses: undo exp and log
    You can find the inverse of f(x)=3(2x+1)−4f(x) = 3(2^{x+1}) - 4.