Find the derivative of: $\displaystyle {\left({7}-{4}{x}\right)}^{{2}}$. [Hint: expand first.]

Preview Question 6 Part 1 of 2  

Now, find the equation of the tangent line to the curve at (1, 9). Write your answer in $\displaystyle {m}{x}+{b}$ format

$\displaystyle {y}=$Preview Question 6 Part 2 of 2