Թեմա՝ լոգարիթմական ֆունկցիա
բանաձև՝
аx = b
x = logab
a > 0 b > 0
a=/ 1

55. ա) log381
x = log381 = 4
բ) log216
x = log216 = 4
գ) log0,11000
log1/101000 = -3
դ) lg0,001
10-3 = 0,001
56. ա) log25√4 = x
2x = 5√4
2x = 41/5
2x = (22)1/5
2x = 22/5
x = 2/5
բ) lg100/√10 = x
10x = 100/√10
10x = 102/101/2
10x = 102 — 1/2
10x = 103/2
x = 3/2
գ) log5253√5
5x = 52 3√5
5x = 52 * 51/3
x = 2 + 1/3 = 6 + 1/3 = 7/3
57. ա) 52log512
2log512 = log5122 = 144
բ) 84log83
4log83 =log834 = 81
գ) 70,5log716
0,5log716 = log7160,5 = √16 = 4
դ) 9log38 = 32log38
log382 = 64
59. ա) 8x = 5
x = log85

60. ա) log6x = 1
x = 61