Question

O resultado de 5 x 2 - ( 2 x 2 + 5 ) + ( x – 8 ) - ( 3x – 1) é:
a) 7 x 2 – 2x – 4 b) 3 x2 – 4x – 4 c) 3 x 2 – 2x – 12 d) 7 x 2 – 4x – 12

Answer 1

Resposta:

5 x 2 - ( 2 x 2 + 5 ) + ( x – 8 ) - ( 3x – 1) =

10-(2x2+5)+(x-8)-(3x-1) =

10-4-5+x-8-3x+1 =

-6+x-3x =

-6-2x =

-2x = -6

2x = 6

x = 3

a) 7 x 2 – 2x – 4 =

14-2x-4 =

10-2x=

2x = -10

x = -5

b) 3 x2 – 4x – 4 =

6-4x-4 =

2- 4x =

2(1-2x)

c) 3 x 2 – 2x – 12 =

6-2x-12 =

-6-2x =

-2(3+x) =

-6-2x =

-2x = 6

x = -3

d) 7 x 2 – 4x – 12 =

14-4x-12 =

2-4x =

2(1-2x)