When solving equation by factoring.

Question

How do we check our answer? Can you demonstrate with an example?

Answer 1

Do you mean something like this?

 

x² + 3x + 2 = 0

 

(x + 2)(x + 1) = 0

 

so x + 2 = 0 and x + 1 = 0

 

then, x = -2 and x = -1

 

to check these, just plug them into the original equation in place of x:

 

(-2)2 + 3(-2) + 2 = 0 ??

          4 + -6 + 2 = 0 ??

             -2    + 2 = 0 ??

                       0 = 0  true!

 

repeat with x = -1 ....