Question

4x+a=6x, for x

Answer 1

x = a/2

Answer 2

a=6x-4x
a=2x
a/2=x

Answer 3

You ultimate goal on all linear problems are to get the "x" alone (in this case)
To do so so, we must collect like terms.
4x + a = 6x

And to do so, we must substract 4x on both sides:

4x + a = 6x
-4x -4x
-----------
0x + a = 2x
or simply:
a = 2x

Now again, we need to get "x" alone. This time, we need to divide:
a = 2x
- --
2 2

a/2 = x

Answer 4

Thank you so much KatrinaKaif for explaining it!

Answer 5

The pleasure is mine Hogie :-)