text: # How do you multiply (x + -3)(10x + -20)?
  
  Aug 8, 2017
  
  $10 {x}^{2} - 50 x + 60$
  
  #### Explanation:
  
  $\left(x + - 3\right) \left(10 x + - 20\right)$
  
  $=$ $\left(x - 3\right) \left(10 x - 20\right)$
  
  $=$ $x \cdot \left(10 x - 20\right) - 3 \cdot \left(10 x - 20\right)$
  
  $=$ $\left(10 {x}^{2} - 20 x\right) - 30 x + 60$
  
  $=$ $10 {x}^{2} - 20 x - 30 x + 60$
  
  $=$ $10 {x}^{2} - 50 x + 60$