Find the lengths of the segments with variable expressions

EF = 10;   AD = 3 ;     BC = 17        

Step-by-step 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                                                    

the entire expression should be subtracted from 30. to subtract the quantity, distribute the negative sign, which changes the signs on the terms. so, the –2 changes to positive and gets added to 30 instead of subtracted from it.

hope this ! ^w^