Question

Решите системы неравенств:
3(х + 8) > 9 -2х
and
3(х + 4) ≥ х + 5

Answer 1

$\begin{cases}3(x+8)>9-2x\\3(x+4)\geq x+5\end{cases}\Rightarrow\begin{cases}3x+24>9-2x\\3x+12\geq x+5\end{cases}\Rightarrow\begin{cases}3x+24>9-2x\\3x+12\geq x+5\end{cases}\Rightarrow\\\\\Rightarrow\begin{cases}3x+2x>9-24\\3x-x\geq 5-12\end{cases}\Rightarrow\begin{cases}5x>-15\\2x\geq-7\end{cases}\Rightarrow\begin{cases}x>-3\\x\geq-3,5\end{cases}\Rightarrow x\in(-3;\;+\infty)$