Need To Know
ϑ The idea behind the quadratic formula
ϑ How do we obtain the quadratic formula ?
ϑ How to use the quadratic formula
ϑ How to memorizing the quadratic formula
(9.3.B)
Obtaining the Quadratic Formula
Solve:
ax2 + bx + c = 0
The Quadratic Formula
For ax2 + bx + c = 0,
How to use the formula
Example: Find the coefficients.
3x2 - 7x + 11 = 0
Solve :
x2 – 3x + 2 = 0
How To Solve
1. Put equation in
standard form
(it must equal 0).
2. Find a, b, c
3. Plug into the
formula & simplify
Solve :
4y2 – 4y – 3 = 0
Solve :
x2 – 4x + 4 = 5
Solve:
7x2 = 6x – 2
9.3 Conclusion
Ways to Solve Quadratic Equations
1. Factoring method (see 6.6)
(Set up: equation must = 0)
2. Square root method
(Set up: " squared stuff " by itself)
3. Completing the square method
(Set up: the leading coefficient = 1)
4. Quadratic Formula
(Set up: equation must = 0)
| Rating |
Doable |
| Easy |
Not
always |
| Easy |
Not
always |
| Hard |
Always |
Memorize the Quadratic Formula
THE STORY
A negative b ee could not decide about going
to a radical party. At the party some square
bees were playing poker. One of the bees
threw down 4 aces. The whole thing was
over at 2 am.
