Question

POR FAVOR URGENTE, com os cálculos!!!!!

Answer 1

Explicação passo-a-passo:

∆= b² - 4.a.c

x= - b ±√∆/2.a

a) x²-5x +6=0

a= 1

b= -5

c= 6

∆=(-5)² -4.1.6

∆= 25 - 24

∆= 1

x= - (-5) ±√1/2.1

x= 5 ±1/2

x1= 5+1/2= 6/2= 3

x2= 5-1/2= 4/2= 2

S = { 3 , 2}

b) 3x² -7x +4=0

∆= (-7)² -4.3.4

∆= 49 - 48

∆= 1

x= - (-7) ±√1/2.3

x= 7 ± 1/6

x1= 7+1/6= 8/6= 4/3

x2= 7-1/6= 6/6= 1

S = { 4/3, 1 }

c) 2x² -3x -5=0

∆= (-3)² - 4.2.(-5)

∆= 9 + 40

∆= 49

x= - (-3) ±√49/2.2

x= 3 ±7/4

x1= 3+7/4= 10/4= 5/2

x2= 3-7/4= -4/4= -1

S= { 5/2 , -1}

2)

2x² -6x -4=0

a) f(3)= 2.3² - 6.3 -4

f(3) = 2.9 - 18 -4

f(3)= 18 - 18 -4

f(3) = - 4

b) f(-2) = 2.(-2)² - 6 . (-2) -4

f(-2) = 2.4 + 12 -4

f(-2) = 8 +12 -4

f(-2) = 20 -4

f(-2) = 16

3)

x² -3x -4=0

∆= (-3)² -4.1.(-4)

∆= 9 + 16

∆= 25

x= - (-3) ±√25/2.1

x= 3 ±5/2

x1= 3+5/2= 8/2= 4

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

S= { 4 , -1}

Soma das raízes

4 + (-1)=

4 - 1=

3