Răspunsuri

2014-04-22T13:19:42+03:00
Aducem la acelasi numitor
30(x+3)+20(x+4)+15(x+5)+12(x+6)+10(x+7)=300
30x+90+20x+80+15x+75+12x+72+10x+70=300
87x+387=300
87x=300-387
87x=-87
x=-1