Step-by-step explanation
We can affirm by the triangle midsegment theorem that the segment DF is half of the segment BC, therefore:
Plugging in the terms into the expression:
Applying the distributive property and removing the parentheses:
Subtracting -3x to both sides:
Subtracting terms:
Adding +3 to both sides:
Adding numbers:
In conclusion, the value of x is 6