 легенда19 
                                                17.04.2020 14:59
                                                
                                                легенда19 
                                                17.04.2020 14:59
                                             kaluznavikusa9 
                                                17.04.2020 14:59
                                                
                                                kaluznavikusa9 
                                                17.04.2020 14:59
                                             Uknowmyname 
                                                17.04.2020 14:59
                                                
                                                Uknowmyname 
                                                17.04.2020 14:59
                                             Dasha20061104 
                                                17.04.2020 14:58
                                                
                                                Dasha20061104 
                                                17.04.2020 14:58
                                             arinasuykova 
                                                17.04.2020 14:58
                                                
                                                arinasuykova 
                                                17.04.2020 14:58
                                             nusbek 
                                                17.04.2020 14:58
                                                
                                                nusbek 
                                                17.04.2020 14:58
                                             H1biki 
                                                17.04.2020 14:58
                                                
                                                H1biki 
                                                17.04.2020 14:58
                                            
x²-2x=9
x²-2x-9=0
D=4+36=40
x1=(2-2√10)/2=1-√10
x2=1+√10
x=√(x²-2x+8)
x≥0
x²=x²-2x+8
2x=8
x=4