Answer:
-13
Explanation:
There's a lot of terms there that make it look complicated, but once you combine like terms you'll see it's a simple one.
6d -12 -d = 9d + 53 + d
Let's first just combine the d's on both sides:
(6d - d) - 12 = (9d + d) + 53
5d - 12 = 10d + 53
Do you understand what I did there? I just added together "like terms" on both sides.
Now let's move 5d to the other side by subtracting it from both sides:
-12 = 5d + 53
Follow that?
Now move the 53 over by subtracting it from both sides:
-65 = 5d
Good with that?
Let's turn it around, because that's the norm:
5d = -65
And then how do we get d by itself? We divide by 5:
d = -65/5 = -13
You should always check your work. So plug -13 in for d in the equation you were given:
6(-13) - 12 -(-13) = 9(-13) + 53 - 13
-78 - 12 + 13 = -117 + 53 - 13
-77 = -77 So our answer checks out, yay. And we're done.