Bài 5:
=>x+1+5 chia hết cho x+1
=>5 chia hết cho x+1
=>\(x+1\in\left\{1;-1;5;-5\right\}\)
=>\(x\in\left\{0;-2;4;-6\right\}\)
Bài 4:
a: =-30+3=-27
b: \(=-4-7=-11\)
c: \(=25\left(-85-15\right)=25\cdot\left(-100\right)=-2500\)
d: \(=-60:5+\left(-12\right)\cdot\left(-2\right)\)
\(=-12+24=12\)