The first term is 5. The sequence goes by 2. And 23 is the 9th term. 9x2=18
23-18=5
6a+12=2(3a-8)
6a+12=6a-16
-12. -12
6a=6a-4
-6a -6a
0=-4
no solution because the equation is false.
The answer to the above question can be explained as under -
We know that, the sum of angles of triangle is 180°.
So, vertex angle plus base angles are equal are equal to 180°.
Let the vertex angle be represented by "v" and base angles be represented by "b".
Thus, v + b + b = 180°
So, v + 2b = 180°
Next, the question says, the vertex angle is 20° less than the sum of base angles.
Thus, 2b - 20° = v
<u>Thus, we can conclude that the correct option is A) v + 2b = 180°, 2b - 20° = v</u>
