Question

$x^{2} -9x+20=0$

Answer 1

x² - 9x + 20 = 0

Δ = (-9)² - 4 * 1 * 20

Δ = 81 - 80

Δ = 1

x = - (-9) + - √1 / 2.1

x' = 9 + 1 / 2 

x' = 5

x" = 9 - 1 / 2

x" = 4

S = {5, 4}