EF = 5x - 4, HG = 3x + 4
The given figure is an rectangle EFGH
From the properties of rectangle EFGH:
The length of opposite sides of rectangle are always equal
So, EF = HG, EH = FG
Susbtitute the value of EF
EF = HG
5x - 4 = 3x + 4
5x -3x = 4 + 4
2x = 8
x = 8/2
x = 4
For the length of EF = 5x - 4
Substitute x = 4,
EF = 5x - 4
EF = 5(4) - 4
EF = 20 - 4
EF = 16
Answer : EF = 16