The base angles of an isosceles triangle are equal
The base angles are 15 degrees, while the vertex angle is 150 degrees
The base angles are given as:
Base = (6a- 3) and (a + 12)
So, we have:

Collect like terms


Divide both sides by 5

Substitute 3 for a in Base = (6a- 3),



So, the base angle is 15 degrees.
The vertex angle is calculated using:

So, we have:


Hence, the vertex angle is 150 degrees
Read more about isosceles triangles at:
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Answer:
The answer would be:
B. ∠DEC is an exterior angle.
Step-by-step explanation: Your welcome
Answer:
A filled in circle indicates "or equal to" in a graphing situation. If it's open it means anything less than or greater then that number depending on whatever your graph looks like.
Hopefully this helped!
Answer:

Step-by-step explanation:
Slope intercept formula is y=mx+b
(m) is slope
(b) is the y intercept
We'll find slope first.
slope formula is

y2 and x2 are the y and x values of the second equation and y1 and x2 are the y and x values of the first equation.
So we just put the given values into our equation.

Simplify

Now we put this into our y=mx+b
y=0/-3x+b
now we need the (b)
to do this we take the values of one of the coordinates (doesn't matter which) and replace the (y) and (x) in our equation with them.


Solve
1=0+b
b=1
Put this in our formula

Hope this helps! If you have any questions on how I got my answer feel free to ask. Stay safe!
Answer:
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