Nhị thức \(f\left( x \right) = 3x + 2\) nhận giá trị âm khi: 

\(\dfrac{{32}}{5}\)

\(\dfrac{{16}}{5}\)

\(\dfrac{{64}}{5}\)

\(\dfrac{{4}}{5}\)

\(x \in \left( {0;2} \right) \cup \left( {3; + \infty } \right).\)

\(x \in \left( { - \infty ;0} \right) \cup \left( {3; + \infty } \right).\)

\(x \in \left( { - \infty ;0} \right] \cup \left( {2; + \infty } \right).\)

\(x \in \left( { - \infty ;0} \right) \cup \left( {2;3} \right).\)

\(x \in \left[ { - \dfrac{1}{3};\dfrac{1}{3}} \right].\)

\(x \in \left( { - \infty ; - \dfrac{1}{3}} \right) \cup \left( {\dfrac{1}{3}; + \infty } \right).\)

\(x \in \left( { - \infty ; - \dfrac{1}{3}} \right] \cup \left[ {\dfrac{1}{3}; + \infty } \right).\)

\(x \in \left( { - \dfrac{1}{3};\dfrac{1}{3}} \right).\)

\(x \in \left[ {\dfrac{1}{2};1} \right].\)

\(x \in \left( { - \infty ; - \dfrac{1}{2}} \right) \cup \left( {1; + \infty } \right).\)

\(x \in \left( { - \infty ;\dfrac{1}{2}} \right] \cup \left[ {1; + \infty } \right).\)

\(x \in \left( {\dfrac{1}{2};1} \right).\)