Question

determine as raizes das equacoes abaixo
x²-49=0
5x² ( ) 10x=0
x²+6x+9=49

Answer 1

x² - 49 = 0
x² = 49
x = 7

5x² - 10x = 0

Δ = b²-4.a.c
Δ = 10² - 4.5.0
Δ = 100 - 0
Δ = 100

√ 100 = 10

-(-b) +- √Δ / 2.a
-(-10) - 10 / 2.5
 x1 = 10 - 10 / 10 = 0/10 = 0
 x2 = 10 + 10 / 10 = 20/10 = 2

x² + 6x + 9 = 49
x² + 6x = 40
x² + 6x - 40 = 0

Δ = b² -4.a.c
Δ = 6² - 4.1.(-40)
Δ = 36 + 160
Δ = 196

√196 = 14

-b +-√Δ / 2.a

x1 =  -6-14 / 2.1 = -20/2 = -10
x2 = -6 +14/ 2.1 = 8/2 = 4