Question

Calcule o valor numérico de 2x³-4x²+x-1 para:
a)x=0
b)x=-1
c)x=1/2
d)x=-1/3​

Answer 1

2x³-4x²+x-1

a)x=0

2 . 0³-4 . 0²+0 -1

0 - 0 + 0 - 1

-1

b)x=-1

2 . (-1)³-4 . (-1)² - 1 -1

2 . (-1) -4 . 1 -2

-2 -4 -2

-8

c)x=1/2

2 . (1/2)³-4 . (1/2)² + 1/2 -1

2 . (1/8) -4 . (1/4) -1/2

2/8 -4/4 -1/2

2/8 -1 -1/2

2/8 -4/8 -1

-2/8 -8/8

-10/8

d)x=-1/3​

2 . (1/3)³-4 . (1/3)² + 1/3 -1

2 . (1/27) -4 . (1/9) -2/3

2/27 -4/9 -2/3

2/27 -12/27 - 18/27

-28/27

Answer 2

2x³-4x²+x-1

a)x=0

2 . 0³-4 . 0²+0 -1

0 - 0 + 0 - 1

-1

b)x=-1

2 . (-1)³-4 . (-1)² - 1 -1

2 . (-1) -4 . 1 -2

-2 -4 -2

-8

c)x=1/2

2 . (1/2)³-4 . (1/2)² + 1/2 -1

2 . (1/8) -4 . (1/4) -1/2

2/8 -4/4 -1/2

2/8 -1 -1/2

2/8 -4/8 -1

-2/8 -8/8

-10/8

d)x=-1/3​

2 . (1/3)³-4 . (1/3)² + 1/3 -1

2 . (1/27) -4 . (1/9) -2/3

2/27 -4/9 -2