(х+у)при х=2^7-5,y=^7-3

х = 2^7 - 5
y =2^7 - 3

x + y = (2^7 - 5) + (2^7 - 3) = 2^7 - 5 + 2^7 - 3 = 2^7 + 2^7 - 5 - 3 = (2^7 + 2^7) + (-5 - 3) = 2^7 * (1 + 1) - 8 = 2^7 * 2 - 8 = 2^8 - 8 = 2^8 - 2^3 = 2^3 * (2^5 - 1) = 8 * (32 - 1) = 8 * 31 = 248

Ответ: 248.