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}