see its very simple actually.
we are doing a same operation both side , it nullify the impact.
lets take this example. your mom gives you and your brother 10 chocolate each.
now your mother takes 5 choclate back from each , both of you will be like ok, no issue , mom has taken same number of choclate from both.
if your mom gives back you 10 more chocolates to each of you , both of you will be like super happy bcoz both hav3 same number choclate. so same impact to both.
similar numbers are like that . if c is positive number than it leaves same impact on both side.
so we can say inequality holds true for each case if c is positive.
a + c > b + c
a - c > b - c
a × c > b × c
a / c > b/c
if c is negative then doing addition and subtraction still have the same impact. but multiplication and division leave the impact and change the inequality.
so if c is negative , addition and subtraction still holds the inequality
a + c > b + c
a - c > b - c
division and multiplication change the inequality
a × c < b × c
a / c < b/c
you can assume a = 2 , b = 1 and c = 1 for psitive scenerio and c = -1 for negative scenario.
put it in equation and check if it true or not. play with it.