Question

Equação de 2o Grau
x2-6x-9=0
e
2x2-8x-10=0

Answer 1

A) x² - 6x - 9 = 0

A= 1
B= - 6
C= - 9

∆= b² - 4ac

∆= (-6)² - 4 . 1 . (-9)
∆= 36 + 36
∆= 72

x= - b ± √∆/2a

x= - (-6) ± √72/2 . 1
x= 6 ± √72 / 2

x'= 6 + √72/2
x''= 6 - √72/2

S= ( 6 + √72/2 , 6 - √72/2)

B)2x² - 8x - 10 = 0

A= 2
B= - 8
C= - 10

∆= b² - 4ac

∆= (-8)² - 4 . 2 . (-10)
∆= 64 + 80
∆= 144

x = - b ± √∆/2 . a

x= - (-8) ± √144/ 2 . 2
x= 8 + 12/4

x' = 8 + 12/4 = 20/4 = 5
x''= 8 - 12/4 = - 4/4 = - 1

S= ( 5 , - 1)