0
\\t^2-8t-20=0
\\t^2-10t+2t-20=0
\\t(t-10)+2(t-10)=0
\\(t-10)(t+2)=0
\\t=-2\notin D, \ t=10
\\10^x=10
\\x=1
" alt="\\100^x-80*10^{x-1}-20=0
\\10^{2x}-0,1*8*10^x-20=0
\\10^{2x}-8*10^x-20=0
\\10^x=t>0
\\t^2-8t-20=0
\\t^2-10t+2t-20=0
\\t(t-10)+2(t-10)=0
\\(t-10)(t+2)=0
\\t=-2\notin D, \ t=10
\\10^x=10
\\x=1
" align="absmiddle" class="latex-formula">