If | A-3 | + | B-4 | = 0, find the value of ab. my elder brother and sister can help me

If | A-3 | + | B-4 | = 0, find the value of ab. my elder brother and sister can help me

|a-3|+|b-4|=0
|a-3|=0
a=3
|b-4|=0
b=4
So a = 3, B = 4, ab = 3 * 4 = 12