How do I find x in these equations

For problems 9 through 12, we'll use the same set of steps. Recall that any parallelogram has the property that the adjacent angles are supplementary. This means close by angles add to 180. Each of the four diagrams show pairs of adjacent angles.

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In problem 9, we have the following steps

(79x-1) + (102) = 180

79x + 101 = 180

79x = 180-101

79x = 79

x = 79/79

x = 1

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Problem 10 is the same idea

(85) + (30x+5) = 180

30x+90 = 180

30x = 180-90

30x = 90

x = 90/30

x = 3

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Problem 11

(55)+(9x+17) = 180

9x+72 = 180

9x = 180-72

9x = 108

x = 108/9

x = 12

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Problem 12

(3x+12)+(132) = 180

3x+144 = 180

3x = 180-144

3x = 36

x = 36/3

x = 12

penjen420 penjen420 · Answer 2 · 2020-12-03T10:58:58+01:00

Answer:

9. X = 1

10. X = 3

11. X = 12

12. X = 12

Step-by-step explanation:

9.

1) 79x - 1 + 102 = 180

2) 79x + 101 = 180

3) Subtract 101 from both sides

4) 79x = 79

5) x = 1

10.

1) 85 + 30x + 5 = 180

2) 30x + 90 = 180

3) Subtract 90 from both sides

4) 30x = 90

5) x = 3

11.

1) 55 + 9x + 17 = 180

2) 9x + 72 = 180

3) Subtract 72 from both sides

3) 9x = 108

4) X = 12

12.

1) 3x + 12 + 132 = 180

2) 3x + 144 = 180

3) Subtract 144 from both sides

4) 3x = 36

5) x = 12

All answers have been checked by plugging the X back into the equation.