Question

cat este x+1 intrun modul egal cu 7 ​

Answer 1

|x+1|=7 => x+1 aparține D7

D7={1,-1,7,-7}

x+1=1 => x=1-1=0

x+1=-1 => x=-1-1=-2

x+1=7 => x=7-1=6

x+1=-7 => x=-7-1=-8

x={0,-2,6,-8}