1. I CAN . . .
-solve equations using the Quadratic Formula.
lesson 9.4a

2. ~formula can solve all quadratic equations.
Quadratic formula
~formula can solve all quadratic equations.

3. Example 1: 8 ± (–8)² – 4 (1) (15) x = 2 (1) 8 ± 4 x = 2 1 –8 15
A = _____ B = _____ C= _____ 8
(–8)²
– 4
(1)
(15)
x = 2
(1) 8 4
x = 2

4. Continued . . . ± 8 4 x = 2 8 ± 2 x = 2 8 + 2 = 8 – 2 = 2 2 x = 3

5. Example 2: –2 ± (2)² – 4 (3) (–7) x = 2 (3) –2 ± 88 x = 6
a = ___ b = ___ c = ___ 3 2 –7 –2
(2)²
– 4
(3)
(–7)
x = 2
(3) –2 88
x = 6

6. Continued . . . ± –2 88 x = 6 –2 ± 9.4 x = 6 –2 + 9.4 = –2 – 9.4 = 6 6
–2 ± 9.4
x = 6
– =
–2 – 9.4 = 6 6
x = 1.2
x = –1.9

7. Your turn 2: –5 ± (5)² – 4 (1) (3) x = 2 (1) –5 ± 13 x = 2
a = ___ b = ___ c = ___ 1 5 3 –5
(5)²
– 4
(1)
(3)
x = 2
(1) –5 13
x = 2

8. Continued . . . ± –5 13 x = 2 –5 ± 3.6 x = 2 –5 + 3.6 = –5 – 3.6 = 2 2
–5 ± 3.6
x = 2
– =
–5 – 3.6 = 2 2
x = –0.7
x = –4.3

9. Are you a master??
a b c

10. Today’s assignment
9.4A Worksheet