F. 4 MATH

log√5x - 2/log(3x) = 1/2
log√5 + logx - 2 / (log3 + logx) = 1/2
log 5 + 2logx - 4 / (log3 + logx) = 1
(log 5 + 2logx) (log3 + logx) - 4 = log3 + logx
2(logx)² + (2log3 + log5)logx + log3 log5 - 4 = log3 + logx
2(logx)² + (2log3 + log5 - 1)logx + log3 log5 - log3 - 4 = 0
2(logx)² + 0.65321 logx - 4.14363 = 0
logx = [ - 0.65321 ± √ ( 0.65321² - 4(2)(-4.14363) ) ] / 4
logx = 1.28531 or logx = - 1.61192
x = 19.29 or x = 0.0244


2012-04-20 14:51:17 補充：
log√(5x-2) / log(3x) = 1/2

2log√(5x-2) = log(3x)

log(√(5x-2))² = log(3x)

log(5x-2) = log(3x)

5x - 2 = 3x

x = 1