Question
Multiply polynomial $ \, \color{blue}{ 7k-6 } \, $ by $ \, \color{orangered}{ k+7 }$.
Answer
$$ \left( \color{blue}{7k-6} \right) \cdot \left( \color{orangered}{k+7} \right) = 7k^2+43k-42 $$
Explanation
In this example we are multiplying two binomials so FOIL method can be used.
$$ \begin{aligned} \left( \color{blue}{ 7k-6}\right) \cdot \left( \color{orangered}{ k+7}\right) &= \underbrace{ \color{blue}{7k} \cdot \color{orangered}{k} }_{\text{FIRST}} + \underbrace{ \color{blue}{7k} \cdot \color{orangered}{7} }_{\text{OUTER}} + \underbrace{ \left( \color{blue}{-6} \right) \cdot \color{orangered}{k} }_{\text{INNER}} + \underbrace{ \left( \color{blue}{-6} \right) \cdot \color{orangered}{7} }_{\text{LAST}} = \\ &= 7k^2 + 49k + \left( -6k\right) + \left( -42\right) = \\ &= 7k^2 + 49k + \left( -6k\right) + \left( -42\right) = \\ &= 7k^2+43k-42; \end{aligned} $$This page was created using
Polynomial Operations Calculator