Log x + log (x - 6) =3

x = 3 + sqrt(e^3 + 9)

Step-by-step explanation:

Solve for x over the real numbers:

log(x) + log(x - 6) = 3

Hint: | Combine logarithms.

log(x - 6) + log(x) = log(x (x - 6)):

log(x (x - 6)) = 3

Hint: | Eliminate the logarithm from the left hand side.

Cancel logarithms by taking exp of both sides:

x (x - 6) = e^3

Hint: | Write the quadratic polynomial on the left hand side in standard form.

Expand out terms of the left hand side:

x^2 - 6 x = e^3

Hint: | Take one half of the coefficient of x and square it, then add it to both sides.

Add 9 to both sides:

x^2 - 6 x + 9 = e^3 + 9

Hint: | Factor the left hand side.

Write the left hand side as a square:

(x - 3)^2 = e^3 + 9

Hint: | Eliminate the exponent on the left hand side.

Take the square root of both sides:

x - 3 = sqrt(e^3 + 9) or x - 3 = -sqrt(e^3 + 9)

Hint: | Look at the first equation: Solve for x.

Add 3 to both sides:

x = 3 + sqrt(e^3 + 9) or x - 3 = -sqrt(e^3 + 9)

Hint: | Look at the second equation: Solve for x.

Add 3 to both sides:

x = 3 + sqrt(e^3 + 9) or x = 3 - sqrt(e^3 + 9)

Hint: | Now test that these solutions are correct by substituting into the original equation.

Check the solution x = 3 - sqrt(e^3 + 9).

log(x) + log(x - 6) ⇒ log((3 - sqrt(e^3 + 9)) - 6) + log(3 - sqrt(e^3 + 9)) = 2 i π + 3 ≈ 3 + 6.28319 i:

So this solution is incorrect

Hint: | Check the solution x = 3 + sqrt(e^3 + 9).

log(x) + log(x - 6) ⇒ log(3 + sqrt(e^3 + 9)) + log((3 + sqrt(e^3 + 9)) - 6) = 3:

So this solution is correct

Hint: | Gather any correct solutions.

The solution is:

x = 3 + sqrt(e^3 + 9)

9514 1404 393

  x = 3 + √1009 ≈ 34.765

Step-by-step explanation:

Take the antilog and solve the resulting quadratic.

  x(x -6) = 10^3

  x^2 -6x +9 = 1009 . . . . . . add (-6/2)^2 to complete the square

  (x -3)^2 = 1009 . . . . . . . . . write as a square

  x = 3 + √1009 ≈ 34.765 . . . . . square root and add 3

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Only the positive root makes any sense, since the log of a negative number is not defined (in real numbers).

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For the graph, we subtracted 3 so we are looking for the x-intercept where f(x)=0.

its 50 miles away from the starting point