Bài giải
\(\text{Ta có : }\left|3x+14\right|\ge\text{ }0\text{ Dấu " = " xảy ra khi }3x+14=0\text{ }\Rightarrow\text{ }3x=-14\text{ }\Rightarrow\text{ }x=-\frac{14}{3}\)
\(\Rightarrow\text{ }F=-79+\left|3x+14\right|\ge-79\)
\(\Rightarrow\text{ }Min\text{ }F=-79\text{ khi }x=-\frac{14}{3}\)