решить неравенство 4x +7<=2/x

4х+7≤ [tex] \frac{2}{x} [/tex]
4х²+7х≤2
4х²+7х-2≤0
D=7²-4*4*(-2)=49+32=81
[tex] x_{1} = \frac{-7+9}{2*4} = \frac{2}{8} = \frac{1}{4} [/tex]
[tex] x_{2} = \frac{-7-9}{8} = \frac{-16}{8} = -2[/tex]