[latex]a) \ \left ( ( 6 frac{3}{7} -( frac{3}{4}x-2) : 0,35) * 2,8-1 frac{3}{4} ight ) : frac{1}{20} = 235 \ \left ( ( 6 frac{3}{7} -( frac{3}{4}x-2): frac{35} {100}) * frac{28}{10}-1 frac{3}{4} ight ) * frac{20}{1} = 235 \ \left ( ( 6 frac{3}{7} -( frac{3}{4}x-2* frac{20}{7} ) * 2,8-1 frac{3}{4} ight ) * frac{20}{1} = 235[/latex] [latex]left ( ( frac{45}{7} - frac{15}{7}x+ frac{40}{7} ) * frac{14}{5}-1 frac{3}{4} ight ) * frac{20}{1} = 235 \ \left ( ( frac{85}{7} - frac{15}{7}x ) * frac{14}{5}- frac{7}{4} ight ) * 20 = 235 \ \ left ( 34 - 6x -1 frac{3}{4} ight ) * 20 = 235[/latex] [latex]680 - 120x - 35 = 235\ \-120x = 235+35-680 \ \ -120x = -410 /:(-120) \ \x=frac{410}{120}\ \ x=frac{41}{12} \ \ x=3frac{5}{12}[/latex] [latex]b)\ \ 315 : [36 -(frac{432}{5x-198} + 15)] =21\ \ 5x-198 eq 0 \ \ 5x eq 198 /:5\ \x eq frac{198}{5}\ \ x eq 39frac{3}{5}[/latex] [latex]315 : [36 -(frac{432 +15(5x-198)}{5x-198} )] =21 \ \315 : [36 -(frac{432 +75x-2970}{5x-198} )] =21 \ \315 : [36 -(frac{75x-2538}{5x-198} )] =21[/latex] [latex]315 : [ frac{36(5x-198)-(75x-2538)}{5x-198} ] =21 \ \315 : [ frac{180x-7128 - 75x+2538 }{5x-198} ] =21 \ \315 : frac{105x-4590}{5x-198}=21\ \ 315 * frac{5x-198}{105x-4590} =21[/latex] [latex]frac{1575x-62370}{105x-4590} -21 =0 \ \ frac{1575x-62370 -21 (105x-4590)}{105x-4590} =0 \ \frac{1575x-62370 -2205x+96390 }{105x-4590} =0 \ \frac{-630x+34020 }{105x-4590} =0 [/latex] [latex]105x-4590 eq 0 \ \ 105x eq 4590 /:105 \ \x eq frac{4590}{105} \ \-630x+34020 = 0\ \ -630x=-34020 /:(-630) \ \x = frac{34020}{630} \ \x= 54[/latex]
