Step 1 :
Factor out common factor $ \color{blue}{ 5v } $:
$$ 40u^2v+150uv^2+35v^3 = 5v ( 8u^2+30uv+7v^2 ) $$Step 2 :
$ 8u^2+30uv+7v^2 $ can be written as
$$ 8u^2+30uv+7v^2 = \left( 4u+v \right) \left( 2u+7v \right)$$The explanation for this step cannot be generated.