Answer:
EF=20
Step-by-step explanation:
EF is midsegment of the triangle so the equation is
AB/2=EF
7x-2/2=2x+8
7x-2=4x+16
7x-4x=16+2
3x=18
x=18/3
x=6
EF=2×6+8
=12+8
=20