what is the product. ( x-9)(x+8)

Question

Find  the product. (X-9)(x+8)

Answer 1

 ( x -9)( X+ 8) =

 

 ( X - 9 ) X + 8 ( X - 9)  =     Distribute it twice

 

 

 X² - 9X + 8X - 72 =

 

  X² - X   - 72

 

 

Generally : ( X + a ) ( X + b ) = X² + ( a  + b ) X  + ab

 

 

Answer 2

Using FOIL (First, Outside, Inside, Last):

 

First:      x(x)  = x²

 

Outside: x(8) = 8x

 

Inside:  -9(x) = -9x

 

Last:     -9(8) = -72

 

x² + 8x - 9x - 72

 

 

 

Answer:

 

x² - x - 72