Answer:
z = -9
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
Equality Properties
Algebra I
- Terms/Coefficients/Degrees
Explanation:
Step 1: Define
-21 = z - (-6 - 2z)
Step 2: Solve for z
- Distribute negative: -21 = z + 6 + 2z
- Combine like terms: -21 = 3z + 6
- Isolate z term: -27 = 3z
- Isolate z: -9 = z
- Rewrite: z = -9