[tex]\bold{a)} \ 3(4+2x)=42 \ \Leftrightarrow \ 12+6x=42 \\ \Rightarrow \ 6x=42-12=30 \ \Leftrightarrow \ x=\frac{30}{6}=\boxed{5}; \\ \bold{b)} \ (23-x):6=3 \ \Leftrightarrow \ 23-x=3\cdot8=18 \\ \Rightarrow \ x=23-18=\boxed{3}; \\ \bold{c)} \ 5(3x-9)=60 \ \Leftrightarrow \ 15(x-3)=60 \ \Leftrightarrow \ x-3=\frac{60}{15}=4 \\ \Rightarrow \ x=3+4=\boxed{7}; \\ \bold{d)} \ (23-5x):9=2 \ \Leftrightarrow \ 23-5x=2\cdot9=18 \\ \Rightarrow 5x=23-18=5 \ \Leftrightarrow \ x=\frac{5}{5}=\boxed{1};[/tex]
[tex]\bold{e)} \ 24:(5-x)=6 \ \Leftrightarrow \ 5-x=\frac{24}{6}=4 \\ \Rightarrow \ x=5-4=\boxed{1}.[/tex]
