Respuesta :

13. 5y + 10 = 6y - 2....vertical angles are equal
      5y - 6y = -2 - 10
      -y = - 12
       y = 12 <==

     2x + 40 = 110...vertical angles are equal
     2x = 110 - 40
     2x = 70
      x = 70/2
      x = 35 <==
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14. x = 0.5x + 17.5....vertical angles are equal
      x - 0.5x = 17.5
      0.5x = 17.5
      x = 17.5 / 0.5
      x = 35 <==

      y = 145 <== vertical angles are congruent
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15. x + 42 = 52
      x = 52 - 42
      x = 10 <==

     6y + 8 = 7y - 12
    6y - 7y = -12 - 8
          - y = -20
            y = 20 <==
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16. 75 + 4y + 25 = 180.....supplementary angles = 180
      4y + 100 = 180
      4y = 180 - 100
      4y = 80
        y = 80/4
        y = 20 <==

       75 + 2x - 5 = 180...supplementary angles = 180
       2x + 70 = 180
       2x = 180 - 70
       2x = 110
         x = 110/2
         x = 55 <==
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17. 3y + 13 + 5y - 1 = 180...supplementary angles = 180
     8y + 12 = 180
    8y = 180 - 12
    8y = 168
      y = 168/8
      y = 21 <==

    11x + 16 + 8x + 12 = 180
    19x + 28 = 180
    19x = 180 - 28
    19x = 152
       x = 152/19
       x = 8 <==
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18. 3x + 17 = 5x - 47...vertical angles are equal
      3x - 5x = -47 - 17
      -2x = - 64
         x = -64/-2
         x = 32 <==

       2y + 9 = 3y - 20
       2y - 3y = -20 - 9
       -y = -29
        y = 29 <==
     
13. 110=2x+40
       x=35
5y+10=6y-2 
        y=12
14.
y=145
      x=0.5x+17.5 
         x=35
15. 
52=x+42
         x=10
6y+8=7y-12
         y=20
16. 
75+2x-5=180
     x=55
75+4y+25=180
     y=20
17. 
11x+16+8x+12=180
              x=8
3y+13+5y-1=180
            y=21
18. 
3x+17=5x-47
           x=32
2y+9=3y-20
       y=29