a: A nguyên
=>x-5+7 chia hết cho x-5
=>\(x-5\in\left\{1;-1;7;-7\right\}\)
=>\(x\in\left\{6;4;12;-2\right\}\)
b: B nguyên
=>3x-6+7 chia hết cho x-2
=>\(x-2\in\left\{1;-1;7;-7\right\}\)
=>\(x\in\left\{3;1;9;-5\right\}\)
c: C nguyên
=>căn x-2+5 chia hết cho căn x-2
=>\(\sqrt{x}-2\in\left\{1;-1;5;-5\right\}\)
=>\(x\in\left\{9;1;49\right\}\)
d: D nguyên
=>2căn x+6-7 chia hết cho căn x+3
=>căn x+3=7
=>x=16