SOLUTION: 2logx-log7=log112

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Question 151169: 2logx-log7=log112
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
Solve for x:
2log%28x%29-log%287%29+=+log%28112%29 Apply the power rule for logs to the first term.
log%28x%5E2%29-log%287%29+=+log%28112%29 Now apply the quotient rule.
log%28%28x%5E2%2F7%29%29+=+log%28112%29 Apply the identity rule: If log%28a%29+=+log%28b%29 then a+=+b
x%5E2%2F7+=+112 Multiply both sides by 7.
x%5E2+=+784 Take the square root of both sides.
x+=+28 Only the positve value of the square root is valid.
Check:
2log%28x%29-log%287%29+=+log%28112%29 Substitute x = 28.
2log%2828%29-log%287%29+=+log%28112%29
log%28%2828%5E2%2F7%29%29%29+=+log%28112%29
log%28%28784%2F7%29%29+=+log%28112%29
log%28112%29+=+log%28112%29