[tex]\it a)\ \ 1-\{2-\[[3-(4-x)]\}=5 \Rightarrow 1-2+\[[3-(4-x)]=5 \Rightarrow \\ \\ \Rightarrow 3-4+x=6 \Rightarrow x-1=6 \Rightarrow x=7[/tex]
[tex]\it b)\ \ -4,5+0,4(1+6x-3)=-3-1,4x \Rightarrow 2,4x-0,8=1,5-1,4x \Rightarrow \\ \\ \Rightarrow 3,8x=2,3\bigg|_{\cdot10} \Rightarrow 38x=23 \Rightarrow x=\dfrac{23}{38}[/tex]
