(39+x)-84=78

To solve the equation (39+x) - 84 = 78, we need to isolate the variable x.

First, let's simplify the equation:

(39 + x) - 84 = 78 39 + x - 84 = 78 x - 45 = 78

Now, to isolate x, we need to get x by itself.

Adding 45 to both sides of the equation:

x - 45 + 45 = 78 + 45 x = 123

Therefore, the solution to the equation (39+x) - 84 = 78 is x = 123.