Answer:
x = 15
Explanation:
Let's start by copying down the equation.
6 + 4x + 3 = 6x - 21
Let's simplify this equation and we get,
4x + 9 = 6x - 21
Now, we can add 21 to both sides to isolate 6x on one side. Then, we get...
4x + 30 = 6x
Now, we minus 4x from both sides to get rid of it.
Then we get...
2x = 30
Thus, x = 15