Step-by-step explanation:
1.

2.

First equation: Your equation is given.
Second equation: Distribute by multiplying every number in the parentheses by the number outside it.
3rd equation: Combine like terms by adding 4x to both sides.
4th equation: Combine like terms by subtracting 14 from both sides.
5th equation: Divide both sides by -2, the coefficient of x.
Answer: d. 102
Why
If 6 is 78 then 5 is 102 and since 1,3,5,and 7 are equal 3 is 102. [180-78=120(180 is the straight line)]
One of the 4 options prolly D