Step 1: First we have to write polynomials in descending order.

$$ \begin{aligned} P(x) &= 7x-9 \\ Q(x) &= x+2 \\ \end{aligned} $$

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

$$ \begin{aligned} \left( \color{blue}{ 7x-9}\right) \cdot \left( \color{orangered}{ x+2}\right) &= \underbrace{ \color{blue}{7x} \cdot \color{orangered}{x} }_{\text{FIRST}} + \underbrace{ \color{blue}{7x} \cdot \color{orangered}{2} }_{\text{OUTER}} + \underbrace{ \left( \color{blue}{-9} \right) \cdot \color{orangered}{x} }_{\text{INNER}} + \underbrace{ \left( \color{blue}{-9} \right) \cdot \color{orangered}{2} }_{\text{LAST}} = \\ &= 7x^2 + 14x + \left( -9x\right) + \left( -18\right) = \\ &= 7x^2 + 14x + \left( -9x\right) + \left( -18\right) = \\ &= 7x^2+5x-18; \end{aligned} $$

Polynomial Operations Calculator