Let $f(x) = 2 x + 3 \sqrt{ x}$. Then: $f'( 4 ) =$ .

Use the previous answer to find the equation of the tangent line to the curve $y = 2 x + 3 \sqrt{ x}$ at the point $( 4 , f(4) )$. Write your answer in the form $y = mx+b$ where $m$ is the slope and $b$ is the y-intercept.
Tangent line equation: .