30-2 = 4x
28 = 4x
Divide both sides by 4 to eliminate the 4.
x=7
Since -6 +6 can be rearranged to 6-6 using the communicative property, we get 6-6 =0 . In addition, -120+(-6) is essentially having -120+ 1*(-6), and 1 times a number is simply that number, so we have -120-6=-126
1 7/24 is the correct answer I will show you how to get it if needed.
Answer: 
Step-by-step explanation:
Let be "x" the original volume of the solution (in milliliters) before the acid was added and "y" the volume of the solution (in milliliters) after the addition of the acid.
Set up a system of equations:

Applying the Substitution Method, you can substitute the second equation into the first equation and then solve for "x":
Answer:
20
Step-by-step explanation:
20+20=40