Question

Me ajudaaaaa A) 3. (2x+3) -4. (x-1) =3 B) 7.(x-1) -2. (x-5) = x-5 C) 3. (5-x) -3. (1-2x) =42

Answer 1

vamos a solução


A) 3. (2x+3) -4. (x-1) =3
6x+9-4x+4 = 3
2x+13=3
2x = 3-13
x = -10/2
x = -5

B) 7.(x-1) -2. (x-5) = x-5
7x-7-2x+10 = x-5
5x+3 = x-5
5x - x = -5-3
4x = -8
x = -8/4
x = -2

C) 3. (5-x) -3. (1-2x) =42
15-3x -3+6x=42
15+3x= 42+3
3x = 45-15
x = 30/3
x = 10

Answer 2

A) 3·(2x+3)-4·(x-1) = 3:

Expandir 3·(2x+3):

3·2x + 3·3 = 6x + 9

Expandir -4·(x-1):

-4·x-4·(-1) = -4x + 4

⇒ 6x + 9 - 4x + 4 = 3

⇒ 2x + 13 = 3 ⇒ 2x = 10 ⇒ x = -5

B) 7·(x-1) - 2·(x-5) = x - 5:

Expandir 7·(x-1):

7·x + 7·(-1) = 7x - 7

Expandir -2·(x-5):

-2·x - 2·(-5) = -2x + 10

= 7x - 7 - 2x + 10 = 5x + 3

⇒5x + 3 = x-5 ⇒ 4x = -8 ⇒ x = -2

C) 3·(5-x)-3·(1-2x) = 42:

Expandir 3·(5-x):

3·5 + 3·(-x) = 15 - 3x

Expandir -3·(1-2x):

-3·1 - 3(-2x) = -3 + 6x

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

⇒3x + 12 = 42 ⇒ 3x = 30 ⇒ x = 10