Respuesta :

let b = x

a = x + 773

x + x + 773 = 177973

2x + 
773 = 177973

2x = 
177973 - 773

2x = 177200

x = 
177200/2

x = 88600

The other is x + 773,  =  8860
0 + 773 = 89373

Each country is 
88600 and 89373 square kilometers.