In this example we are multiplying two binomials so FOIL method can be used.
$$ \begin{aligned} \left( \color{blue}{ x+5}\right) \cdot \left( \color{orangered}{ x+5}\right) &= \underbrace{ \color{blue}{x} \cdot \color{orangered}{x} }_{\text{FIRST}} + \underbrace{ \color{blue}{x} \cdot \color{orangered}{5} }_{\text{OUTER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{x} }_{\text{INNER}} + \underbrace{ \color{blue}{5} \cdot \color{orangered}{5} }_{\text{LAST}} = \\ &= x^2 + 5x + 5x + 25 = \\ &= x^2 + 5x + 5x + 25 = \\ &= x^2+10x+25; \end{aligned} $$