3.4 Solving Quadratic Equations by Factoring

3.4 Solving Quadratic Equations by Factoring

Get out a piece of paper and a pencil

Remember Back...

• Before Thanksgiving Break, we reviewed how to factor

• Let's see this one more time:

   $0=x^2+9x+20$  

We will use factoring to solve quadratics

Last week we used graphing:

Now: Zero Product Property

• For any real number a and b, if ab=0 then a=0, b=0, or both a nd b are zero.

• Basically the only way to multiply and get zero is to multiply by zero.

So from before:

•  $0=x^2+9x+20$ 

•  $0=\left(x+5\right)\left(x+4\right)$  

Let's See Another:

•  $0=16x^2+8x$  

Multiple Select

Find the solutions:

 $0=x^2-8x+12$  

• x=-2

• x=6

• x=2

• x=-3

Multiple Select

Find the solutions:

 $0=x^2+7x-8$  

• x=1

• x=-1

• x=8

• x=-8