Multiplicera varje term i första parentesen med varje term i andra parentesen: $$ \underbrace{6x \cdot 4x}_{ \displaystyle 24x^{ 2 } } + \underbrace{6x \cdot \left( -1 \right) }_{ \displaystyle -6x } + \underbrace{6 \cdot 4x}_{ \displaystyle 24x } + \underbrace{6 \cdot \left( -1 \right) }_{ \displaystyle -6 } $$