31.5 = a - 34.4
add 34.4 to both sides:
a = 65.9
x + 76.32 = 164.89
subtract 76.32 from both sides:
x = 88.57
36 = a - 64
add 64 to both sides:
a = 100
96 + y = 187
subtract 96 from both sides:
y = 91
x - 9 = 26
add 9 to both sides:
x = 35
x + 23 = 92
subtract 23 from both sides:
x = 69