[tex]\begin{gathered} f(x)=6x^2-x^3 \\ f^{^{\prime}}(x)=12x-3x^2 \\ f^{^{^{\prime}}}(1)=12(1)-3(1)^2 \\ f^{^{\prime}}(1)=12\text{ -3} \\ f^{^{\prime}}(1)=9 \\ y-y_{1\text{ }}=m(x-x_1) \\ m=f^{^{\prime}}(1) \\ y_1=\text{ 5} \\ x_1=1 \\ y\text{ -5 =}9(x\text{ -1)} \\ y\text{ = 5 +9x -9} \\ y=9x\text{ -}4 \end{gathered}[/tex]
