SOLUTION: I need to know how to get to the answer which is 7. Thank you! :-) -[2z

Question 10314: I need to know how to get to the answer which is 7. Thank you! :-)
-[2z - (5z + 2)] = 2 + (2z + 7)
Found 2 solutions by rapaljer, prince_abubu:
Answer by rapaljer(4551) (Show Source):
You can put this solution on YOUR website!
To avoid confusion, remove the parentheses first, working the problem on the inside of the brackets first.
-[2z - (5z+2)] = 2 + (2z +7)
-[2z - 5z - 2] = 2 + 2z + 7

Combine like terms:
-[-3z - 2] = 9 + 2z

Now remove the brackets, the same as parentheses:
3z + 2 = 9 + 2z

Get the variables all on the left side by subtracting 2z from each side:
3z - 2z + 2 = 9 + 2z - 2z
z + 2 = 9

Subtract 2 from each side:
z + 2 - 2 = 9 - 2
z = 7

R^2 at SCC

Answer by prince_abubu(198) (Show Source):
You can put this solution on YOUR website!
This problem involves multiple parentheses. You must "strip" this from the inside-out. ALWAYS get rid of the innermost parentheses FIRST.

<---------- start here

<------ We got rid of the inner parentheses on the left side. Notice that the 2 became a -2. The reason is because the expression REALLY said -1(5z + 2). We just don't write the 1. We know it's there. We then distributed that -1 to the 5z and the 2.

<------ We got rid of the outer-level parentheses. Notice that the signs changed on the left side. This is due to multiplying all terms in the parentheses by that -1.

<------ We combined like terms without transfering terms across the equals sign.

<----- Subtracted 2z from both sides. This is the same thing as transferring the 2z from the right side to the left side. As the 2z gets transferred, it also changes signs. When on the left side, it combined with 3z because they're like terms to get 1z or z.

<---- subtract 2 from both sides, or you just know that z = 7 by looking at the equation above.

SOLUTION: I need to know how to get to the answer which is 7. Thank you! :-) -[2z - (5z + 2)] = 2 + (2z + 7)