Răspunsuri

2014-04-12T10:45:48+03:00
3x+15x-5(1-x²)=x²-6x+9+4x²-4x+1+13
3x+15x-5+5x²=5x²-10x+23    5x² se simplifica
18x-5=-10x+23
18x+10x=23+5
28x=28
x=1