Answer:
EF = 10; AD = 3 ; BC = 17
Explanation:
The median (EF) of a trapezoid equal half the sum of the length of the two bases of the trapezoid (AD and BC)
EF = 1/2 (AD + BC)
x = 1/2( x - 7 + 2x - 3)
x = 1/2 (3x - 10)
2x = 3x - 10 Multiply all terms by 2 or x = 3/2x - 5
-x = -10 x - 3/2x = -5
x = 10 -1/2x = -5
x = 10
So EF = 10
AD = x - 7 BC = 2x - 3
AD = 10 - 7 BC = 2(10) - 3
AD = 3 BC = 20 - 3
BC = 17