Question

Qual é o valor

3.x(2x+3)-4.( x-1)=3
2.(3-x)=3.(x-4)+15
3.(5-x)-3.(1+2x)=42
7.( x-1)-2.(x-5)=x-5

Answer 1

Oi....

a)

3.(2x + 3) - 4 .(x - 1) = 3

6x + 9 - 4x + 4 = 3

2x = 3 - 4 - 9

2x = - 10

x = - 10/2

x = - 5

b)

2.(3 - x) = 3.(x - 4) + 15

6 - 2x = 3x - 12 + 15

- 2x - 3x = - 12 + 15 - 6

- 5x = - 3 ⇒( - 1)

5x = 3

x = 3/5

c)

3.(5 - x) - 3.(1 + 2x) = 42

15 - 3x - 3 - 6x = 42

- 3x - 6x = 42 + 3 - 15

- 9x = 30 ⇒( - 1)

9x = - 30

x = - 30/9 ÷ 3

x = - 10/3

d)

7.(x - 1) - 2.(x - 5) = x - 5

7x - 7 - 2x + 10 = x - 5

7x - 2x - x = - 5 - 10 + 7

4x = - 8

x = - 8/4

x = - 2

Espero ter ajudado