Hello!
The answer is:
The value of "x" in the equation, is -7.

Why?
To solve this problem, we need to isolate the variable by applying distributive property and then, adding/subtracting like terms.
The distributive property states that:

Also, we need to remember that like terms are terms that share the same variable with the same exponent.

In the example, we were only able to add the first two terms since both share the same exponent (2).
So, we are given the equation:

Hence, the value of "x" in the equation, is -7.

Have a nice day!