Question

equação biquadrada 9x²-13×+4=0​

Answer 1

9x² - 13x + 4 = 0

9(x²)² - 13x² + 4 = 0

x² = y

9y² - 13y + 4 = 0

a = 9

b = -13

c = 4

∆ = b² - 4.a.c

∆ = (-13)² . 4.9.4

∆ = 169 - 144

∆ = 25

y = -b ± √∆ / 2.a

y = -(-13) ± √25 / 2.9

y = 13 ± 5 / 18

y = 13 + 5 / 18

y = 18/18

y = 1

y = 13 - 5 / 18

y = 8/18

y = 4/9

x² = 1

x = √1

x = 1 e x = -1

x² = 4/9

x = √4/√9

x = 2/3 e x = -2/3

S = { 1; -1; 2/3; -2/3 }