Answer:
The value of x = -6
Explanation:
We know that if the line CD is parallel to line EF, then their slopes will be the same.
In other words:
slope
= slope

As we know that the slope between two points will be:

Let's find the slope of CD
as


Now, let's find the slope of EF
as


As we already pointed out that






Therefore, the value of x = -6