Răspuns:
1500-(820-2000*a+2400)/80=700
1500-(3220-2000*a)/80=700
1500-20(161-100*a)/80=700 am dat factor comun in paranteze, dupa simplific 20 cu 80
1500-(161-100*a)/4=700 aducem la acelasi numitor comun si scapam de fractie
6000-(161-100*a)=2800
6000-161+100*a=2800
5839+100*a=2800
100*a=2800-5839
a=-3039/100
a=-30.39
