Question

Решите неравенство: log0,4 (1,9 x – 1,3) ≥ -1

Answer 1

log 0.4+log (1.9x-1.3) >= - 1
log (1.9x-1.3) >= - 1- log 0.4
log (1.9x-1.3) >= - log 10 - log 0.4
log (1.9x-1.3) >= - log 4
log (1.9x-1.3) >=  log 1/4
1.9x -1.3 >=0.25
1.9 x >= 1.55
x >= 1.55/1.9
x >= 0.8