Verified answer

A) x² 2x 1 = 0

Δ= b² -4.a.c

Δ = 2² - 4.1.1

Δ = 4 - 4

Δ = 0

x = - ( b ) ± √Δ / 2.a

X = -( 2 ) ± √0 / 2 .1

X= -2 ± 0 / 2

x' = -2 / 2 = -1

x"= -2 / 2= -1

b) x² 5x 6 = 0

Δ= b² -4.a.c

Δ= 5² -4.1.6

Δ= 25 - 24

Δ= 1

x = -(b) ± √Δ/2.a

x = -(5) ± √1/2.1

x = -5 ± 1 /2

x' = -5 1/2 =-4/2=-2

x"= -5-1 / 2= 6 / 2= 3

x² + 2x + 1 = 0

d² = 2² - 4*1*1 = 0

x = (-2/2) = -1

x² + 5x + 6 = 0

d² = 5² - 4*6 = 25 - 24 = 1

x1 = (-5 + 1)/2 = -2

x2 = (-5 - 1)/2 = -3

pronto