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
![EF](https://img.qammunity.org/2021/formulas/mathematics/middle-school/5r7zk5kmtke6oihkyjkfpkiytrjannh6ld.png)
As we know that the slope between two points will be:
![\mathrm{Slope}=(y_2-y_1)/(x_2-x_1)](https://img.qammunity.org/2021/formulas/mathematics/middle-school/nrlo6m8wdo12tyt9h1mdgp9vd4866t2plg.png)
Let's find the slope of CD
as
![m\:\left(CD\right)=(-4-16)/(2-x)](https://img.qammunity.org/2021/formulas/mathematics/college/o8ggaaqkyefifal4jobceug6otox4n55fo.png)
![=-(20)/(2-x)](https://img.qammunity.org/2021/formulas/mathematics/college/y6hit5a2qfk9l6dyoy49kftvqi7czng2my.png)
Now, let's find the slope of EF
as
![m\left(EF\right)=(4-14)/(-2-\left(-6\right))](https://img.qammunity.org/2021/formulas/mathematics/college/ij5gvniut1zyon0efws48po4ljaei9gnk0.png)
![=-(10)/(4)](https://img.qammunity.org/2021/formulas/mathematics/college/xkipwxjtt6pfnxgcafz8zwcuq5wa3e29vg.png)
As we already pointed out that
![m\left(CD\right)=\:m\left(EF\right)](https://img.qammunity.org/2021/formulas/mathematics/college/413iy3vycyv2gngncowxbxozjzfknll5ou.png)
![=-(10)/(4)](https://img.qammunity.org/2021/formulas/mathematics/college/xkipwxjtt6pfnxgcafz8zwcuq5wa3e29vg.png)
![-20\cdot \:4=-\left(2-x\right)\cdot \:10](https://img.qammunity.org/2021/formulas/mathematics/college/ipwpimtfpmqn1ql1m8bju03hubsk0tdp68.png)
![(-\left(2-x\right)\cdot \:10)/(-10)=(-80)/(-10)](https://img.qammunity.org/2021/formulas/mathematics/college/xcc9u1ceposxm29zbvb6j15oblvn7nd1i9.png)
![2-x=8](https://img.qammunity.org/2021/formulas/mathematics/college/wvillmb15rnhpoocbbvfv6u6u8096evdyl.png)
![x=-6](https://img.qammunity.org/2021/formulas/mathematics/middle-school/jtwekzgij3fcrgfgworftdh5pt3sh0g4c2.png)
Therefore, the value of x = -6