Solve the inequality r+7 is lesser than or equal to 12

R+7(<=)12

r+7 should result: 0,1,2,3,4,5,6,7,8,9,10,11,12

so, here's the process:

r+7= 0
r= 0-7
r= -7

r+7= 1
r= 1-7
r= -6

r+7= 2
r= 2-7
r= -5

r+7= 3
r= 3-7
r= -4

r+7= 4
r= 4-7
r= -3

r+7= 5
r= 5-7
r= -2

r+7= 6
r=6-7
r= -1

r+7= 7
r= 7-7
r= 0

r+7= 8
r= 8-7
r= 1

r+7= 9
r= 9-7
r= 2

r+7= 10
r= 10-7
r= 3

r+7= 11
r= 11-7
r= 4

r+7= 12
r= 12-7
r= 5

r = { -7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5}

Really long apparently