\(\left(d\right):y=3x+1\)
Goi \(A\left(x_0;y_0\right)\) la tiep diem \(y'=3x^2\)
Vi tiep tuyen song song voi (d) \(\Rightarrow pttt:y=3x+b\left(b\ne1\right)\)
\(\Rightarrow y'\left(x_0\right)=3\Leftrightarrow3x^2_0=3\Leftrightarrow x_0=\pm1\)
\(x_0=1\Rightarrow y_0=0\)
\(\Rightarrow pttt:y=9x-9\)
\(x_0=-1\Rightarrow y_0=-2\)
\(\Rightarrow pttt:y=9\left(x+1\right)-2=9x+7\)
=> co 2 tiep tuyen