Question

Resolva as equações:
a) x² -25 = 0
b) 4x² - 36 = 0
c) x² - 64 = 0

Answer 1

a) x² - 25 = 0

a = 1

b = 0

c = -25

Δ = b² - 4 .a .c

Δ = 0² - 4 .1 .(-25)

Δ = 100

x = -b ± $\sqrt{Delta}$ /2 .a

x = 0 ± $\sqrt{100}$ /2 .1

x = 0 ± 10 /2

x' = 10 /2 = 5

x" = -10 /2 = -5

  S = (5, -5)

b) 4x² - 36 = 0

a = 4

b = 0

c = -36

Δ = b² - 4 .a .c

Δ = 0² - 4 .4 .(-36)

Δ = 576

x = -b ± $\sqrt{Delta}$ /2 .a

x = 0 ± $\sqrt{576}$ /2 .4

x = 0 ± 24 /8

x' = 24 /8 = 3

x" = -24 /8 = -3

  S = (3, -3)

c) x² - 64 = 0

a = 1

b = 0

c = -64

Δ = b² - 4 .a .c

Δ = 0² - 4 .1 .(-64)

Δ = 256

x = -b ± $\sqrt{Delta}$ /2 .a

x = 0 ± $\sqrt{256}$ /2 .1

x = 0 ± 16 /2

x' = 16 /2 = 8

x" = -16 /2 = -8

  S = (8, -8)