✔ 最佳答案
log(x/2) * log(3/x) = log(x/6) ...... [1]
(logx - log2) * (log3 - logx) = logx - log6
log3 logx - (logx)² - log2 log3 + log2 logx - logx + log6 = 0
- (logx)² + (log3 + log2 - 1) logx - (log2 log3 + log6) = 0
(logx)² - (log3 + log2 - 1) logx + (log2 log3 + log6) = 0
設 u = logx,
u² - (log3 + log2 - 1) u + (log2 log3 + log6) = 0 ...... [2]
則logα 及 logβ 為方程式 [2] 的兩根。
方程式 [2] 的兩根之和:
logα + logβ = log3 + log2 - 1
log(αβ) = log3 + log2 - log10
log(αβ) = log(3*2/10)
log(αβ) = log(3/5)
αβ = 3/5
原方程式的兩根之積 αβ = 3/5