Answer:
x = -17/16
General Formulas and Concepts:
Pre-Algebra
Order of Operations: BPEMDAS 
- Brackets 
- Parenthesis 
- Exponents 
- Multiplication 
- Division 
- Addition 
- Subtraction 
Equality Properties 
- Multiplication Property of Equality 
- Division Property of Equality 
- Addition Property of Equality 
- Subtraction Property of Equality 
Explanation:
Step 1: Define
-8 = 16x + 9
Step 2: Solve for x
- [Subtraction Property of Equality] Subtract 9 on both sides: -17 = 16x
- [Division Property of Equality] Divide 16 on both sides: -17/16 = x
- Rearrange/Rewrite: x = -17/16
Step 3: Check
Plug in x into the original equation to verify it's a solution.
- Substitute in x: -8 = 16(-17/16) + 9
- Multiply: -8 = -17 + 9
- Add: -8 = -8
Here we see that -8 does indeed equal -8.
∴ x = -17/16 is the solution to the equation.