Question

a) – 3+(– 2)³ +(– 6)² + [( – 2 – 3)³ ÷ ( – 1 – 4)+( – 3)².( – 2 + 1)²] = ?
b) ( –2 – 1)³+ ( –3)²– [ ( –3 –1 )² ÷ ( –2)³ – ( – 1) ². ( –2 + 3)] = ?
c) x² - 5x + 6 = 0
d) x² - 8x + 12 = 0
e) x² + 2x - 8 = 0
f) 2x² - 8x + 8 = 0
g) x² - 4x - 5 = 0

Answer 1

Resposta:

Explicação passo-a-passo:

A)

– 3+(– 2)³ +(– 6)² + [( – 2 – 3)³ ÷ ( – 1 – 4)+( – 3)².( – 2 + 1)²]

= -3+(-8)+(36)+ [(-5)^3 ÷ (-5)+(9).(-1)^2]

= - 3 - 8 + 36 + [- 125 ÷ (-5) + 9.1]

= - 11 + 36 + [25 + 9]

= 25 + 34

= 59

R.: 59

_______________

b)

= (-2-1)³+ (-3)²-[(-3-1 )² ÷ (-2)³ -(-1) ². (-2+3)]

= (-3)^3 + 9 - [(-4)^2 ÷ (-8) - (1).1 ]

= - 27 + 9 - [ 16 ÷ (-8) - 1]

= - 18 - [ - 2 - 1]

= - 18 - [ - 3]

= - 18 + 3

= - 15

R : - 15

______________

c) x² - 5x + 6 = 0

a = 1; b = - 5; c = 6

/\ = b^2 - 4ac

/\ = (-5)^2 - 4.1.6

/\ = 25 - 24

/\ = 1

x = [ - b +/- \/ /\] /2a

x = [ - (-5) +/- 1]/ 2.1

x = [ 5 +/- 1]/2

x' = (5+1)/2 = 6/2 = 3

x" = (5-1)/2 = 4/2 = 2

R.: {3; 2}

_____________________

d) x² - 8x + 12 = 0

a = 1; b = - 8; c = 12

/\ = b^2 - 4ac

/\ = (-8)^2 - 4.1.12

/\ = 64 - 48

/\ = 16

x = [- b +/- \//\]/2.a

x = [ - (-8) +/- \/16]/2.1

x = (8+/- 4)/2

x = (8+4)/2 = 12/2 = 6

x = (8-4)/2 = 4/2 = 2

R.: {6; 2}

__________________

e) x² + 2x - 8 = 0

a = 1; b= 2; c = - 8

/\ = b^2 - 4ac

/\ = 2^2 - 4.1.(-8)

/\ = 4 + 32

/\ = 36

x = [ - b +/- \/ /\]/2a

x = [ - 2 +/- \/36]/2.1

x= [ - 2 +/- 6]/2

x' = [ - 2 - 6]/2 = - 8/2 = - 4

x" = [- 2 + 6]/2 = 4/2 = 2

R.: {- 4; 2}

_________________

f) 2x² - 8x + 8 = 0. (:2)

x^2 - 4x + 4 = 0

a = 1; b = - 4; c = 4

/\ = b^2 - 4ac

/\ = (-4)^2 - 4.1.4

/\ = 16 - 16

/\ = 0

x = [- b +/- \//\]/2a

x = [ - (-4) +/- 0]/2.1

x = 4/2 = 2

R.: x = 2

_______________

g) x² - 4x - 5 = 0

a = 1; b = - 4; c = - 5

/\ = b^2 - 4ac

/\ = (-4)^2 - 4.1.(-5)

/\ = 16 + 20

/\ = 36

x = [ - b +/- \/ /\]/2a

x = [-(-4) +/- \/36]/2.1

x = [ 4 +/- 6]/2

x' = (4+6)/2 = 10/2 = 5

x" = (4-6)/2 = - 2/2 = - 1

R.: {5; - 1}