<s>[INST] How many zeros does $f(x)= 3x^4 + x + 2 $ have? 
How many zeros does this function have?
  $$f(x)=  3x^4 + x + 2 $$

 [/INST] For $x\ge -2$, we have $(x+2)\ge 0$ and $3x^4>0$, so $f(x)>0$.
For $x<-2$, we have $3x^4+x=x(3x^3+1)=(-x)(-1-3x^3)>(2)(-1+3\cdot 2^3)=46$, so $f(x)>0$.
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