Question

log0,1(1-0.4x)≥-2 помогите пожалуйста

Answer 1

$\displaystyle\bf\\ODZ:\\\\1-0,4x > 0\\\\-0,4x > -1\\\\\boxed{x < 2,5}\\\\\\\log_{0,1}(1-0,4x)\geq -2\\\\1-0,4x\geq 0,1^{-2} \\\\1-0,4x\geq 100\\\\-0,4x\geq 99\\\\x\leq -247,5\\\\Otvet: \ x\in\Big(-\infty \ ; \ -247,5\Big)$