Question

3)Resolva as equações a seguir:a) x² - 9 x+8=0

Answer 1

x² - 9x + 8 = 0

a = 1
b = -9
c = 8

Δ = b² - 4ac
Δ = (-9)² - 4.(1).(8)
Δ = 81 - 32
Δ = 49

$x = \frac{-b \frac{+}{-} \sqrt{b^2-4ac} }{2a}$

$x = \frac{-(-9) \frac{+}{-} \sqrt{49} }{2}$

$x = \frac{9 \frac{+}{-} 7}{2}$

$x' = \frac{9+7}{2}$

$x' = \frac{16}{2}$

$x' = 8$

$x" = \frac{9-7}{2}$

$x" = \frac{2}{2}$

$x" = 1$