How do you solve e^(12-5x) -7 = 123?

1 Answer
Sudip Sinha
Jul 30, 2015

x = 1/5 (12 - ln(130))

Explanation:

e^(12−5x)−7 = 123
=> e^(12−5x) = 123 + 7 = 130 (Add 7 to both sides)
=> 12−5x = ln(130) (Take natural logarithm on both sides)
=> −5x = -12 + ln(130) (Add -12 to both sides)
=> 5x = 12 - ln(130) (Multiply by -1)
=> x = 1/5 (12 - ln(130)) (Divide by 5 on both sides)

If you need, you may use a calculator to get log(130) = 4.8675 . Put this value to get x = 1.4265 .

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