7 задание !!!!!!!!!!!!!!!!!!

Question

7 задание
!!!!!!!!!!!!!!!!!!

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Answer 1

3x²-2x-1≤0
D=4+12=16
x1=(2-4)/6=-1/3
x2=(2+4)/6=1
D(f)∈[-1/3;1]
E(f)∞[0;∞)