123456789
of 9

Solving Equations by Factoring

Here's another kind:

Solve x^2 - 9 = 0 ... remember the difference of two squares?

Factor: ( x - 3 ) ( x + 3 ) = 0

Blobs = 0: x - 3 = 0 or x + 3 = 0 ... Solve: add 3 to both sides of the first equation and subtract 3 from both sides of the second equation, giving solutions of x = 3 and x= -3

{ -3, 3 }

TRY IT:

Solve  x^2 - 25 = 0

OK, let's take this one step further.

What if there were three blobs?

a * b * c = 0

Back to 2nd grade -- fill in the boxes:

3 * ? * 6 = 0

? * 4 * 6 = 0

8 * 9 * ? = 0

a * ? * c = 0

? * b * c = 0

a * b * ? = 0