ОДЗ
2x-7>0; x>3.5
x+1>0;x>-1
x-19.0; x>19
общая ОДЗ x>19
log(3)(2x-7)-2log(3)(x+1)+log(3)(x-19)≥0
log(3)((2x-7)(x-19)/(x+1)^2))≥0
(2x-7)(x-19)/(x+1)^2≥1
(2x-7)(x-19)/(x+1)^2-1≥0
(2x^2-38x-7x+133-x^2-2x-1)/(x+1)^2≥0
(x^2-47x+132)/(x+1)^2≥0
(x-44)(x-3)/(x+1)^2≥0
----(-1)+++[3]----[44]+++
учитывая ОДЗ ответ x=[44;+∞)
Мегатонна
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1) 4³+3^(5) = 64+243 = 507
2) 0,6³-0,4² = 7/125
3) 0,12×5⁴ = 75