009A Sample Midterm 3, Problem 3

Let  ${\displaystyle y=3{\sqrt {2x+5}},x\geq 0.}$
(a) Use the definition of the derivative to compute   ${\displaystyle {\frac {dy}{dx}}.}$
(b) Find the equation of the tangent line to  ${\displaystyle y=3{\sqrt {2x+5}}}$  at  ${\displaystyle (2,9).}$