Answer:
Angle 7 and 8 (the first option)
Step-by-step explanation:
Supplementary angles add up to 180 degrees.
Angles 7 and 8 are 180 degrees total.
7 and 8 are supplementary.
1st option
Brainliest plz if someone else answers
Answer: OPTION B.
Step-by-step explanation:
Given the following System of equations:

You can use the Elimination Method to solve it. The steps are:
1. You can mutliply the second equation by -3.
2. Then you must add the equations.
3. Solve for the variable "y".
Then:

4. Now that you know the value of the variable "y", you must substitute it into any original equation.
5. The final step is to solve for "x" in order to find its value.
Then:

Therefore, the solution is:

Answer:
x = 129°
Step-by-step explanation:
∠ ABD and ∠ DBC are a linear pair and sum to 180° , then
y + ∠ DBC = 180°
107° + ∠ DBC = 180° ( subtract 107° from both sides )
∠ DBC = 73°
the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles , then
x = ∠ DBC + z = 73° + 56° = 129°
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Add '-1' to each side of the equation.
1 + -1 + 3d = 10 + -1
Combine like terms: 1 + -1 = 0
0 + 3d = 10 + -1
3d = 10 + -1
Combine like terms: 10 + -1 = 9
3d = 9
Divide each side by '3'.
d = 3
Simplifying
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