👤

20%x+30%x•80%•x+420=x​

Răspuns :

Răspuns:

Explicație pas cu pas:

20%x+30%x•80%•x+420=x

20x/100+30×80x²/10000+420=x

(20x+24x²)/100-x=-420

20x+24x²-100x=-42000

24x²-80x+420 00=0  /4

6x²-20x-10500=0

3x²-10x-5250=0

x1,2=5±√25+15750/3=5±125,6/3

x1=130,6/3=43,53      

x2=-40,2