SOLUTION: find the inverse of y=log(-3x)-4

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Question 950206: find the inverse of y=log(-3x)-4
Found 2 solutions by MathLover1, stanbon:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

To find an inverse of a function, exchange the x's and y's in the original function and then re-solve for y.
Recall that y+=+log%28+a%2Cx%29 is equivalent to stating that x+=+a%5Ey for any base a+%3E+0.

so,inverse is:
y=log%28-3x%29-4.........exchange the x and y
x=log%28-3y%29-4
x%2B4=log%28-3y%29
x%2B4=log%28-3y%29%2Flog%2810%29
%28x%2B4%29log%2810%29=log%28-3y%29
log%2810%5E%28x%2B4%29%29=log%28-3y%29 .....if log same, then

10%5E%28x%2B4%29=-3y
10%5E%28x%2B4%29%2F-3=y
y=-10%5E%28x%2B4%29%2F3...-> the inverse


Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
find the inverse of y=log(-3x)-4
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1st: Interchange x and y to get:
x = log(-3y)-4
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2nd: Solve for "y"::
log(-3y) = x+4
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-3y = 10^(x+4)
----
y = (-1/3)*10^(x+4)
That is the inverse.
Cheers,
Stan H.
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