Answer:

Explanation:
we know that
The Trapezoid Mid-segment Theorem states that: A line connecting the midpoints of the two legs of a trapezoid is parallel to the bases, and its length is equal to half the sum of lengths of the bases
so In this problem
![EF=(1)/(2)[AD+BC]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/aakb5mzyj48ez42oeu2vulq7at4ppkahgr.png)
substitute the given values
![x=(1)/(2)[(x-6)+(2x-3)]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/pa3431khvfpsupcqvgldlc2nt1v51ec6eh.png)
![x=(1)/(2)[3x-9]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/pzas4zimkyrj3t8n3hwyyvcbhlz40mrrnz.png)

so


