# How do you factor by grouping 56x^3 - 24x^2 + 35x - 15?

Try collecting $7 x$ between the first and third term and $- 3$ between the second and fourth to get:
$7 x \left(8 {x}^{2} + 5\right) - 3 \left(8 {x}^{2} + 5\right)$
Now collect $\left(8 {x}^{2} + 5\right)$:
$\left(8 {x}^{2} + 5\right) \left(7 x - 3\right)$