1) x^2-7x<=0<br>x(x-7)<=0<br>x<=0 и x-7<=0<br> x<=7<br> + - +
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0 7
(x-0)(x-7)<=0 Ответ : [0;7]<br>
20-5x^2>=0
-5x^2>=-20
x^2<=4<br>x<=+2<br>x<=-2<br> + - +
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-2 2
(x+2)(x-2)<=0 Ответ: [-2;2]<br>