Double your pay and half your weight with mathematic

Today wikihow teaches you this self delude calculation, aim to amuse one self and have some laugh. Try it.

3a = 3b
11a = 11b
3a2 = 3ab
11ab = 11b2
3a2 - 11ab = 3ab - 11b2
3a2 - 3ab = 11ab - 11b2
3a2 - 3ab + ab - b2 = 12ab - 12b2
3a(a-b) + b(a-b) = 12b(a-b)
3a + b = 12b
3a = 11b
3b = 11b
3 = 11

(Link) Not so easy hor, like real life.