3x²-24x+21 реш: 3x²-24x+21=0

а=3, в=-24, с=21 Д=в²-4ас=-24²-4*3*21=576-252=324 х= [latex] \frac{-b+- \sqrt{D} }{2a} [/latex] х1= [latex] \frac{24- \sqrt{324} } {2*3} = 6:6=1[/latex] x2= [latex] \frac{24+ \sqrt{324} } {2*3} = 42:6=7[/latex]

D=b²-4ac D=576-252 D=324 x¹=24+√324/6=24+3=27 x²=24-3=21