The complete question is:
Trapezoid JKLM is shown below.
What is the length, in centimeters, of KL ?
A. 12 cm
B. 10 cm
C. 9 cm
D. 6 cm
The mentioned figure is attached.
Answer:

Explanation:
1. KL is the hypotenuse of a right triangle; hence, you can use Pythagora's theorem to find its length.
2. The height 8 cm is one leg of the right triangle.
3. The other leg may be found by difference:

4. Now you can use Pythagora's theorem:

A is the answer your looking for
Answer:
6x +2x squared - 4
that's the answer. you need to group the like terms