Question

ecuaciones de primer grado
a)-7-6x=21-2x
b)0.7x-7=0.3x-5
c)9x-10=4x+25
d)3(y+4)+6=5(y+6)
e)7b+35=-14b+28
f)9x-54=4x+16
g)6(3x-1)-2x=2(2x-5)-8
h)3x-8=x+2

Answer 1

 - 7 - 6x = 21 - 2x

- 6x + 2x = 21 + 7

- 4x = 28

x = 28/-4

x = -7

Solución : 

x = -7
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0.7x - 7 = 0.3x - 5

0.7x - 0.3x =  - 5 + 7

0.4x = 2

x = 2/0.4

x = 5

Solución : 

x = 5
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9x - 10 = 4x + 25

9x - 4x = 25 + 10

5x = 35

x = 35/5

x = 7

Solución : 

x = 7
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3 (y + 4) + 6 = 5 (y + 6)

3y + 12 + 6 = 5y + 30

3y - 5y = 30 - 6 - 12

- 2y = 12

y = 12/-2

y = - 6

Solución : 

y = - 6
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7b + 35 = - 14b + 28

7b + 14b = 28 - 35

21b = - 7

b = -7/21----simplificamos la séptima

b = -1/3

Solución : 

b = -1/3
----------------------------------------------------
9x - 54 = 4x + 16

9x - 4x = 16 + 54

5x = 70

x = 70/5

x = 14

Solución : 

x = 14
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6 (3x - 1) - 2x = 2 (2x - 5) - 8

18x - 6 - 2x = 4x - 10 - 8

18x - 2x - 4x = - 10 - 8 + 6

12x = - 12

x = -12/12

x = -1

Solución : 

x = -1
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3x - 8 = x + 2

3x - x = 2 + 8

2x = 10

x = 10/2

x = 5

Solución : 

x = 5