Change of Base Rule Solutions

Change of Base Rule

The variables a, b, and X are positive real numbers, and a1, b1.

Log of any base: logbX=logaXlogab Common log: logbX=log Xlog b
  • The Change of Base Rule is used to    rewrite logarithms   , so they have the same base.

  • Use the rule when you:

    • have an expression or equation with    multiple    bases.

    • need a    common base    to approximate logs with technology.

Example 8

Write the expression with common logs using the Change of Base Rule. 

  1. logm83

log83logm=3log8logm

Explain

  • Change of Base rule

  • Power rule
  1. log62x+log53

log2xlog6+log3log5=log2+logxlog6+log3log5

Explain

  • Change of Base rule

  • Product rule

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