We can use distribution property to multiply the polynomial by the monomial.
$$ \begin{aligned} \left( x-14 \right) \cdot \color{orangered}{4x} &= x \cdot \color{orangered}{4x} + \left( -14\right) \cdot \color{orangered}{4x} = \\ &= 4x^2-56x \end{aligned} $$