Step 1: First we have to write polynomials in descending order.
$$ \begin{aligned} P(x) &= 5x+5 \\ Q(x) &= 2x+5 \\ \end{aligned} $$In this example we are multiplying two binomials so FOIL method can be used.
$$ \begin{aligned} \left( \color{blue}{ 5x+5}\right) \cdot \left( \color{orangered}{ 2x+5}\right) &= \underbrace{ \color{blue}{5x} \cdot \color{orangered}{2x} }_{\text{FIRST}} + \underbrace{ \color{blue}{5x} \cdot \color{orangered}{5} }_{\text{OUTER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{2x} }_{\text{INNER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{5} }_{\text{LAST}} = \\ &= 10x^2 + 25x + 10x + 25 = \\ &= 10x^2 + 25x + 10x + 25 = \\ &= 10x^2+35x+25; \end{aligned} $$