In this example we are multiplying two binomials so FOIL method can be used.

$$ \begin{aligned} \left( \color{blue}{ 2x^2+5x}\right) \cdot \left( \color{orangered}{ 2x^2-5x}\right) &= \underbrace{ \color{blue}{2x^2} \cdot \color{orangered}{2x^2} }_{\text{FIRST}} + \underbrace{ \color{blue}{2x^2} \cdot \left( \color{orangered}{-5x} \right) }_{\text{OUTER}} + \underbrace{ \color{blue}{5x} \cdot \color{orangered}{2x^2} }_{\text{INNER}} + \underbrace{ \color{blue}{5x} \cdot \left( \color{orangered}{-5x} \right) }_{\text{LAST}} = \\ &= 4x^4 + \left( -10x^3\right) + 10x^3 + \left( -25x^2\right) = \\ &= 4x^4 + \left( -10x^3\right) + 10x^3 + \left( -25x^2\right) = \\ &= 4x^4-25x^2; \end{aligned} $$

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