Предмет: Математика, автор: shef88

решите уравнение х^2-4|х|-21=0​

Ответы

Автор ответа: kaku85
0
х^2-4|х|-21=0

х^2-4х-21=0 х>=0
х^2-4*-х-21=0 х<0

х>=0
х^2-4х-21=0.
х1+х2=4;
х1*х2=21;
х1=-3(не подходит х<0)
х2=7

х<0
х^2+4х-21=0
х1+х2=-4;
х1*х2=21;
х1=3(не подходит, х>0)
х2=-7

ответ: 7;-7;
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