Question

Solve the system:
y = -2x + 9
y = 3x + 9

Answer 1

Answer:

(0, 9)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right  

Equality Properties

• Multiplication Property of Equality
• Division Property of Equality
• Addition Property of Equality
• Subtract Property of Equality

Algebra I

• Terms/Coefficients
• Coordinates (x, y)
• Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define Systems

y = -2x + 9

y = 3x + 9

Step 2: Solve for x

Substitution

1. Substitute in y:                                                                                                3x + 9 = -2x + 9
2. [Addition Property of Equality] Add 2x on both sides:                                5x + 9 = 9
3. [Subtraction Property of Equality] Subtract 9 on both sides:                      5x = 0
4. [Division Property of Equality] Divide 5 on both sides:                                x = 0

Step 3: Solve for y

1. Define equation:                                                                                             y = -2x + 9
2. Substitute in x:                                                                                                y = -2(0) + 9
3. Multiply:                                                                                                           y = 0 + 9
4. Add:                                                                                                                 y = 9