ecuaciones de primer grado

Resolver las siguientes ecuaciones

1. x + 4 = 28

x=28-4

x=24

2. y - 6.5 = 31

y=31+6.5

y=37.5

3. 8z = 40 + 3z

8z-3z=40

5z=40

z=40/5 z=8

4. 10x = - 5x + 60

10x+5x=60

15x=60

x=60/15 x=4

5. - 15y + 3 = - 36 – 18y

-15y+18y=-36-3

3y=39

y=39/3 y=13

6. 2x + 4 + (3x - 4) = 3x + 12

2x +4+3x-4=3x+12

2x+3x-3x=12-4+4

2x=12

x=12/2 x=6

7. 4(3x + 2) - 8 = 5(2x + 3) + 5

12x+8-8=10x+15+5

12x-10x=-8+8+15+5

2x=+20

x=20/2 x=10

8. 15x - 40 - 5x - 20 = 0

15x-5x=+40+20+0

10x=60

x=60/10 x=6.

9. 16 - ( - 2x - 4) - (5x - 3x + 2) = - 4x - ( - 8x + 2)

16 +2x +4 -5x +3x -2 = -4x +8x -2

2x-5x +3x +4x -8x= -16 -4 +2 -2

-8x= -20

x= -20/-8

10. - (7x - 2 + 12) + ( - 5x - 3x + 4) = - ( - x + 7) - (6x - 4 – 7)
    -7x +2 -12 -5x -3x +4= +x -7 -6x +4 +7
    -7x -5x -3x -x +6x=-2 +12 -4 -7 +4 +7
    -10x = 10
    x=-10/10 x=-1
11. - 18 - [ 3(x + 2) + 4] = 21 - [ 6( - 2x - 2) + 1]

-18 – [3x +6 +4] = 21 -[-12x -12 +1]

-18 -3x -6 -4 = 21 +12x +12 -1

-3x -12x = +18 +6 +4 +21 +12 -1

-15x = 60

x= 60/-15 x= -4