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? asked in Science & MathematicsMathematics · 5 years ago

Simultaneous logarithm help?

Doing my revision and I've been given the following question:

Given x and y are both positive, solve the simultaneous equations

log(xy) = 7

log(x/y) = 1

Now, I've tried everything but they haven't given a base so I'm completely stuck. I looked up the answer (I won't say for your sake of discovery) but I can't see how they plug in to the equation at all and it's driving me crazy

1 Answer

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  • ?
    Lv 7
    5 years ago
    Favorite Answer

    log(xy) = 7

    log(x/y) = 1

    log x + log y= 7

    log x - log y = 1

    add the two

    2 log x = 8

    log x = 4 => x=10^4

    log y = 3 => y=10^3

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