5­6­16 Alg L Quadratic Equations Day 1.notebook
ax2 + bx + c = 0
Introduction:
Solving
Quadratic
Equations
DAY 1
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
May 06, 2016
Quadratic equation: polynomial equation of
degree 2
Standard form: ax2 + bx + c = 0
(where a, b, and c are real numbers
and a≠0)
Quadratic equations can be solved by
factoring. Equation must be = 0 before it
can be solved!
GCF S
D2P ial
om
Trin
Factoring Bag
Procedure to Solve Quadratic Equations:
1) Set equation = 0
2) Factor completely
3) Set each factor=0 in a "T" chart.
4) Solve each equation in the chart.
5) Write solution in braces { }.
6) Check each solution.
5­6­16 Alg L Quadratic Equations Day 1.notebook
May 06, 2016
Solve for x: x2 - x - 6 = 0
1. Factor completely (x + 2) (x - 3) = 0
2. Set each factor=0
(x + 2) (x - 3) = 0
in "T" chart.
x+2=0 x-3=0
-2 -2
+3 +3
3. Solve each equation
x = -2
x=3
(called roots)
4. List solution
6. Check
Rewrite
original
equation
Substitute
Solve
{-2, 3}
x2 - x - 6 = 0
x = -2
x=3
?
?
2
2
(3)
-(3)-6
=
0
(-2) -(-2)-6 = 0
?
?
4+2-6=0 9-3-6=0
0≡0
0≡0
5­6­16 Alg L Quadratic Equations Day 1.notebook
Solve for the given variable:
1) x2 + 6x = 0
2) x2 - 12x = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
3) x2 - 36 = 0
4) x2 - 81 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
5) x2 + 6x + 8 = 0
6) x2 - 7x - 18 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
7) 3x2 - 27 = 0
8) 2x2 - 50 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
9) 4x2 - 36x + 80 = 0
10) 5x 2 - 5x - 30 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
11) x 3 - 49x = 0
Now Try These
1) x2 + 15x = 0
2) x2 - 100 = 0
3) x2 - 8x + 12 = 0
4) 2x2 - 242 = 0
5) 3x2 - 15x - 18 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
1) x2 + 15x = 0
2) x2 - 100 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
3) x2 - 8x + 12 = 0
4) 2x2 - 242 = 0
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
5) 3x2 - 15x - 18 = 0
NOW TRY HW SHEET
May 06, 2016
5­6­16 Alg L Quadratic Equations Day 1.notebook
May 06, 2016