The parallelogram is a 4 sided figure whose opposite angles and sides are equal. As such, from the given image we may deduct that
4y - 9 = 2x + 19
and
5x = 2y + 1
from
4y - 9 = 2x + 19
4y = 2x + 19 + 9
4y = 2x + 28
Divide both sides by 2
2y = x + 14
From 5x = 2y + 1
2y = 5x - 1
equating the 2 derived equations
x + 14 = 5x - 1
collect like terms
5x - x = 14 + 1
4x = 15
Divide both sides by 4
x = 15/4
= 3.75
2y = 5 (15/4) - 1
2y = 75/4 - 1
2y = 71/4
divide both sides by 2
y = 71/8
Hence x + y
= 15/4 + 71/8
= 30/8 + 71/8
= 101/8
= 12.625