Question

8o ANO – EXERCÍCIOS : EQUAÇÃO DO 1o GRAU COM UMA INCÓGNITA

RESOLVA AS EQUAÇÕES DO 1o GRAU , NO CONJUNTO R :
1) 11X – 13 = 20
2) 17X + 50 = 7X
3) 9X – 8 = 5X + 20
4) 12X + 21 = 10X + 16
5) 5.(X + 2) – 2.(3X – 1) = 13
6) 5.(X + 2) – 3 .(X + 6) = 40
7) 3 – (3X – 6) = 2X + (4 – X)
8) 4.(X – 2 ) = 4 + 2.(X – 1)

Answer 1

Explicação passo-a-passo:

1) 11X - 13 = 20

11X = 20 + 13

11X = 33

X = 33/11

X = 3

2) 17X + 50 = 7X

17X - 7X = -50

10X = -50

X = -50/10

X = -5

3) 9X – 8 = 5X + 20

9X - 5X = 20 + 8

4X = 28

X = 28/4

X = 7

4) 12X + 21 = 10X + 16

12X - 10X = 16 -21

2X= -5

X=-5/2

5) 5.(X + 2) – 2.(3X – 1) = 13

5X + 10 - 6X +2 = 13

5X - 6X= 13 - 10 - 2

-X= 1 .(-1)

X = -1

6) 5.(X + 2) – 3 .(X + 6) = 40

5X + 10 - 3X -18 = 40

5X - 3X = 40 + 18 -10

2X = 48

X = 48/2

X = 24

7) 3 – (3X – 6) = 2X + (4 – X)

-9X + 18 = 8X - 2X

-9X -8X + 2X = -18

-X = -18 .(-1)

X = 18

8) 4.(X – 2 ) = 4 + 2.(X – 1)

4X - 8 = 4 + 2X - 2

4X - 2X = 4 - 2 + 8

-2X = 10

- X = 10/2

- X = 5 .(-1)

X = -5

Answer 2

Numero 1

$\sf 11x - 13 = 20$

$\sf 11x = 20 + 13$

$\sf 11x = 33$

$\sf x = \dfrac{33}{11}$

$\red{\sf x = 3}$

Numero 2

$\sf 17x + 50 = 7x$

$\sf 17x - 7x = -50$

$\sf 10x = -50$

$\sf x = \dfrac{-50}{10}$

$\red{\sf x = -5}$

Numero 3

$\sf 9x - 8 = 5x + 20$

$\sf 9x - 5x = 20 + 8$

$\sf 4x = 28$

$\sf x = \dfrac{28}{4}$

$\red{\sf x = 7}$

Numero 4

$\sf 12x + 21 = 10x + 16$

$\sf 12x - 10x = 16 - 21$

$\sf 2x = - 5$

$\red{\sf x = - \dfrac{5}{2} }$

Numero 5

$\sf 5(x + 2) - 2(3x - 1) = 13$

$\sf 5x + 10 - 6x + 2 = 13$

$\sf 5x - 6x = 13 - 2 - 10$

$\sf - x = 1$

$\sf - x = 1\cdot ( - 1)$

$\red{\sf x =- 1}$

Numero 6

$\sf 5(x + 2) - 3(x + 6) = 40$

$\sf 5x + 10 - 3x - 18 = 40$

$\sf 5x - 3x = 40 + 18 - 10$

$\sf 2x = 58 - 10$

$\sf 2x = 48$

$\sf x = \dfrac{48}{2}$

$\red{\sf x = 24}$

Numero 7

$\sf 3 - (3x - 6) = 2x + (4 - x)$

$\sf 3 - 3x + 6 = 2x + 4 - x$

$\sf - 3x - 2x + x = - 6 - 3+4$

$\sf - 5x + x = - 9+4$

$\sf - 4x = - 5$

$\sf - 4x = - 5\cdot ( - 1)$

$\sf 4x = 5$

$\red{\sf x = \dfrac{5}{4} }$

Numero 8

$\sf 4(x-2)=4+2(x-1)$

$\sf 4x-8=4+2x-2$

$\sf 4x-2x=4+8-2$

$\sf 2x=10$

$\sf x = \dfrac{10}{2}$

$\red{\sf x = 5}$