Why

Question

given here
x+ = 6
x+6
now
according to mathematics
LHS = RHS
x+ = 6
x-6 = 0
so why it is x+6

Answer 1

x += 6;

is equivalent to x = x + 6, which is assigning the sum of x and 6 to x, not stating the equivalence between LHS and RHS.

Answer 2

x += 6; is just a shortcut method to represent
x = x+6;
Here "=" is assignment operator, this means that new value of x becomes x+6, so you can't do LHS = RHS equivalence here.
In programming "==" means equal to operator and then you may do LHS = RHS.
Don't take the mathematics too seriosly and try to learn about basic syntax and operators etc. used in programming.

Answer 3

The users gived good explanation. In addition, you can use
x -=6; it is equal to x = x-6;

Answer 4

this is not a simple mathematics that we use in maths this is programming in which x+=6 is way to represent x=x+6.where x is increased by 6.