## Calculus 10th Edition

$f''(x)=2940(2-7x)^2$.
Using the Chain Rule: $f'(x)=(5)(-7)(4)(2-7x)^{4-1}=-140(2-7x)^3$. Using the Chain Rule: $f''(x)=(-140)(-7)(3)(2-7x)^{3-1}=2940(2-7x)^2$.