9.2 Quadratic Formula

Check ALL the words that are used to describe a solution to a quadratic equation:

• y-intercept

• x-intercept

• vertex

• root

• zero

What do we look for when solving a quadratic equation using its graph?

• x-intercepts

• y-intercepts

• vertex

What should you do first in solving this equation?

x² + 6x - 13 = 3

• Factor

• Write down: a = 1, b = 6, c = -13

• Subtract 3 from both sides.

• Add 3 to both sides.

In the quadratic equation, a always corresponds with which term?

• x² term

• x term

• constant term

In the quadratic equation, b always corresponds with which term?

• x² term

• x term

• constant term

In the quadratic equation, c always corresponds to which term?

• x² term

• x term

• constant term

Identify the values of A, B, and C

10p² + 7p - 20 = 0

• A=1, B=7, C=-20

• A=10, B=7, C=20

• A=10, B=-7, C=-20

• A=10, B=7, C=-20

 $x=\frac{-\left(b\right)\sqrt{\left(a\right)^2-4ac}}{2b}$  

What is wrong with this formula? Check ALL that apply.

• Missing  $\pm$  after  $-\left(b\right)$  

• The square root should be  $\sqrt{\left(b\right)^2-4ac}$  

• The denominator should be  $2a$  

• There are no errors. It is correct.

 $3x^2-4x=7$  
Which example below uses the quadratic formula  correctly? 
Don't forget that the right side must be zero first!

•  $\frac{-\left(4\right)\pm\sqrt{\left(-4\right)^2-4\left(3\right)\left(-7\right)}}{2\left(3\right)}$  

•  $\frac{-\left(-4\right)\pm\sqrt{\left(-4\right)^2-4\left(3\right)\left(-7\right)}}{2\left(3\right)}$  

•   $\frac{-\left(-4\right)\pm\sqrt{\left(-4\right)^2-4\left(3\right)\left(7\right)}}{2\left(3\right)}$  

In the equation x²+4=0, match each leading coefficient with its correct letter. 

• a=0 b=4 c=0
• a=1 b=4 c=0
• a=1 b=0 c=4