Nov 15, 2011- DISCRIMINANTS

Hey everyone!! It's Vivian from your Pre-cal 30S class :) I'm going to be explaining how to solve for for Discriminants.

The expression to solve for the discriminant is b² - 4ac which comes from the quadratic formula. This allows you to find how many real number solutions are in the quadratic equation without solving the equation or even graphing it.

Example 1: x² - x - 12 = 0
1.) To solve for this you use the formula b² - 4ac
2.) a = 1, b = -1, c = -12
4.) You plug these numbers into your formula.
3.) (-1)² - 4 (1) (-12)
= 1 + 48
= 49
There are 2 real solutions to this example.

REMEMBER WHEN:
Discriminant > 0 there are 2 roots
Discriminant < 0 there are no roots
Discriminant = 0 theres is 1 root

Example 2: x² - x + 2 = 0
1.) Formula: b² - 4ac
2.) Plug in your values a = 1, b = -1, c = 2
3.) (-1)² - 4(1)(2)
= 1 - 8
= -7
The discriminant < 0 therefore there is 0 roots.

My post is the best post out of all posts.... Justkidding I don't have pictures like everyone elses but I tried my best and it's the effort that counts!!!!

Ps: Watch this after you finish your Pre-cal homework because MUSIC HELPS YOUR MIND!!!

The video took too long to upload so here's the link:

http://www.youtube.com/watch?v=H1JgIg38QBU&safety_mode=true&persist_safety_mode=1&safe=active

Ok bye enjoy your day :)