{ 13^(2x+2) - 14*13^(x+2) + 13 ≤ 0
{ 5(x+1,5) - 4x > -3-2,5x
13^(x+1)=13^(x)*13
[red]Замена переменной:
[/red]
13^(x)=t
13^(2x)=(13^(x))^2=t^2
[m]\left\{\begin {matrix}13(13t^2-14t+1) ≤0 \\5x+7,5-4x>-3-2,5x\end {matrix}\right.[/m] t_(1)=1; t_(2)=1/13
[m]\left\{\begin {matrix}\frac{1}{13} ≤ t ≤13 \\3,5x >-10,5\end {matrix}\right.[/m]
[m]\left\{\begin {matrix} 13^{-1} ≤ 13^{x} ≤13 \\x >-3\end {matrix}\right.[/m]
О т в е т. [-1;1]