[tex]a)5*x+4\ \textless \ 16\\
5*x\ \textless \ 16-4\\ 5x\ \textless \ 12\\ x\ \textless \ \frac{12}{5}
[/tex]
x∈( - infinit; 12/5)
[tex]b) 4*x-12 \leq 15\\4x \leq 15+12\\4x \leq 27\\x \leq \frac{27}{4} [/tex]
x∈( - infinit; 27/4]
[tex] c) 5^{2}*x+1\ \textless \ 125\\ 25x\ \textless \ 125-1\\25x\ \textless \ 124\\x\ \textless \ \frac{124}{25} [/tex]
x∈( - infinit; 124/25)
[tex]7*x-3 \leq 5*x+13\\ 7x-5x \leq 13+3\\2x \leq 16\\x \leq 8[/tex]
x∈( - infinit; 8]