Math

QuestionSolve the equation: log3(x5)+log3(x11)=3\log _{3}(x-5)+\log _{3}(x-11)=3.

Studdy Solution

STEP 1

Assumptions1. We are given the equation log3(x5)+log3(x11)=3\log{3}(x-5)+\log{3}(x-11)=3 . We are using the logarithm property logb(a)+logb(c)=logb(ac)\log_b(a) + \log_b(c) = \log_b(ac)3. We are using the logarithm property blogb(a)=ab^{\log_b(a)} = a

STEP 2

First, we can combine the two logarithms on the left side of the equation using the logarithm property logb(a)+logb(c)=logb(ac)\log_b(a) + \log_b(c) = \log_b(ac).
log(x5)+log(x11)=log((x5)(x11))\log{}(x-5)+\log{}(x-11)=\log{}((x-5)(x-11))

STEP 3

So our equation now becomeslog3((x5)(x11))=3\log{3}((x-5)(x-11))=3

STEP 4

Next, we can convert the logarithmic equation to an exponential equation using the property blogb(a)=ab^{\log_b(a)} = a. This gives us(x)(x11)=33(x-)(x-11)=3^3

STEP 5

implify the right side of the equation(x5)(x11)=27(x-5)(x-11)=27

STEP 6

Now, expand the left side of the equationx216x+55=27x^2 -16x +55 =27

STEP 7

Subtract27 from both sides of the equation to set the equation to zerox216x+5527=0x^2 -16x +55 -27 =0

STEP 8

implify the equationx216x+28=0x^2 -16x +28 =0

STEP 9

Now, factor the quadratic equation(x14)(x2)=(x-14)(x-2) =

STEP 10

Finally, solve for x by setting each factor equal to zerox14=0orx2=0x-14=0 \quad or \quad x-2=0

STEP 11

olving for x givesx=14orx=x=14 \quad or \quad x=However, if we substitute x=x= back into the original equation, we get a negative number inside the logarithm, which is undefined. Therefore, the only solution is x=14x=14.

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