Question

X2 -6x+8 maior ou igual 0

Answer 1

Resposta:

x²-6x+8 ≥ 0

x'=[6+√(36-32)]/2=(6+2)/2=4

x''=[6-√(36-32)]/2=(6-2)/2=2

a=1 > 0  ..concavidade para cima

++++++++++++++(2)----------------------------(4)++++++++++++++++++++

(-∞ ; 2]  U [4 ,∞)

Answer 2

Resposta:

x²-6x+8≥0

x ≥ -(-6)+-√(-6)²-4(1)(8)/2(1)

x≥6+-√36-32/2

x≥6+-√4/2

x≥6+-2/2

x' ≥ 6 + 2 / 2

x' ≥ 4

x'' ≤ 6 - 2 / 2

x'' ≤ 2

x' -------------------------------0-\\\\\\\\\\+∞-≻

4

x'' ≺ -∞ \\\\\\\\\-0--------------------------------

2

S = { 2 ≥ x ≥ 4 }