Answer:
Yes, it is
Explanation:
If you substitute the value of x into the equation, we would get:
-18=-2(6+3)
By using BIDMAS (or whatever else people use, BODMAS, PEDMAS), we first have to do the brackets. In the brackets we have 6+3 (which equals 9).
Now our equation can be simplified to -18=-2(9).
Now we simply multiply -2 with 9, as a number next to something in a bracket usually means multiplication. If you multiply a positive by a negative, the product will be negative. Therefore, -9 x 2 = -18.
This proves it is a correct solution.