Răspuns:
[tex]2a+a/2=3a-13\\\\numitor .comun-2\\\\4a+a=6a-26\\\\26=6a-5a\\\\a=26\\\\\\D:11=Crest9= > D=11C+9\\\\99:11=9-nu.convine= > C < 9;C\neq 0\\\\D=8*11+5=93\\\\D=7*11+5=82\\\\D=6*11+5=71\\\\D=5*11+5=60\\\\D=4*11+5=49\\\\D=3*11+5=38\\\\D=2*11+5=27\\\\D=1*11+5=16\\\\S=16+27+38+49+60+71+82+93= > S= 436[/tex]