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

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

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

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

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

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 = –2 – 9.4 = 6 6 x = 1.2 x = –1.9

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

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 = –5 – 3.6 = 2 2 x = –0.7 x = –4.3

Are you a master?? a b c

Today’s assignment 9.4A Worksheet