This is when its best to have the Please Excuse My Dear Aunt Sally, or PEMDAS, down. It actually means Powers Exponents Multiplication Division Addition Subtraction.
You add [x+(x-5)] first (all together) to get [2x-5], which then you do the distributive property with a NEGATIVE 2.
So, -2[2x-5]is -2(2x)-2(-5), or -4x+10
Now you add 18 to that, so 18-4x+10
Now it's 28-4x
or, if you want, it can also be 4(7-x)
Hope this helps!