#5 Parallelograms require that opposite sides be congruent. Therefore we can form a system of linear equations by equating the lengths of opposite sides.
For top and bottom sides, we have 4x+y=8 .............(1) For left and right sides, we have 2x+y=6..............(2)
Subtract (2) from 1 4x+y-(2x+y)=8-6 => 2x=2 => x=1
Substitute x=1 in (1) 4(1)+y = 8 y=4
Answer: x=1,y=4
Check: top side = 4(1)+4=8, ok. left side = 2(1)+4=6, ok.
