We can use distribution property to multiply the polynomial by the monomial.
$$ \begin{aligned} \color{blue}{7x} \cdot \left( x^2+6x-5 \right) &= \color{blue}{7x} \cdot x^2 + \color{blue}{7x} \cdot 6x + \color{blue}{7x} \cdot \left( -5\right) = \\ &= 7x^3+42x^2-35x \end{aligned} $$