標題:
f.5對數函數
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最佳解答:
26) log (3x + 1) - log (x - 1) = log 5 log [(3x + 1)/(x - 1)] = log 5 (3x + 1)/(x - 1) = 5 3x + 1 = 5x - 5 6 = 2x x = 3 27) log x2 + log 2x = log 16 2 log x + log 2 + log x = log 16 3 log x = log 16 - log 2 = log (16/2) = log 8 log x3 = log 8 x3 = 8 x = 2 39) log4 (x + 6) - log4 (6 - 7x) = log4 9 log4 [(x + 6)/(6 - 7x)] = log4 9 (x + 6)/(6 - 7x) = 9 x + 6 = 54 - 63x 64x = 48 x = 3/4
其他解答:
f.5對數函數
發問:
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教我做數,有清楚步驟 26.log(3x+1)-log(x-1)=log5 28.logx^2+log2x=log16 39.log^4(x+6)-log^4(6-7x)=log^4 9最佳解答:
26) log (3x + 1) - log (x - 1) = log 5 log [(3x + 1)/(x - 1)] = log 5 (3x + 1)/(x - 1) = 5 3x + 1 = 5x - 5 6 = 2x x = 3 27) log x2 + log 2x = log 16 2 log x + log 2 + log x = log 16 3 log x = log 16 - log 2 = log (16/2) = log 8 log x3 = log 8 x3 = 8 x = 2 39) log4 (x + 6) - log4 (6 - 7x) = log4 9 log4 [(x + 6)/(6 - 7x)] = log4 9 (x + 6)/(6 - 7x) = 9 x + 6 = 54 - 63x 64x = 48 x = 3/4
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