Question

2. Qual equação de 1° grau tem resposta igual a 21?

A) 5 (2x - 1) = 2 (x + 4)

B) 2x + 1 ÷ 5 (x - 3) = 3 ( x ÷ 1) + x

C) 10- 2 (x + 3) = 8 + 3 (2x + 5) -20

D) 10x - 5 ( 1 + x ) = 3 (2x -2) -20

E) 3x -7 + 2 (x - 1) = 2x - 3​

Answer 1

Resposta:

creio que a resposta seja a D

Answer 2

Resposta:

A) 5 (2x - 1) = 2 (x + 4)

10x-5 =2x+8

10x-2x=8+5

8x=13

x=13/8

B) 2x + 1 ÷ 5 (x - 3) = 3 ( x ÷ 1) + x

2x + 1/5(x-3)=3x/1+x

2x+x/5-3/5=3x+x

$2x + \frac{x}{5} - \frac{3}{5} = 4x \\ 2x - 4x + \frac{x}{5} = \frac{3}{5} \\ - 2x + \frac{x}{5} = \frac{3}{5} \\ \frac{ - 10x + x = 3}{5} \\ - 9x = 3 \\ x = \frac{3}{ - 9} \\ x = \frac{ - 1}{3}$

C) 10- 2 (x + 3) = 8 + 3 (2x + 5) -20

10-2x-6=8+6x+15-20

-2x-6x=8-20+15-10+6

-8x=-1

x=1/8

D) 10x - 5 ( 1 + x ) = 3 (2x -2) -20

10x-5-5x=6x-6-20

5x-6x=-26+5

-x=-21

x=21

E) 3x -7 + 2 (x - 1) = 2x - 3

3x-7+2x-2=2x-3

3x=-3+2+7

3x=6

x=6/3

x=2

resposta letra d)