Question

Solve the equation by subsitiution
x+7y=-2
3x+y=34

Answer 1

x = 12! Hope this helps

Answer 2

(12, -2)

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

Distributive Property

Equality Properties

• Multiplication Property of Equality
• Division Property of Equality
• Addition Property of Equality
• Subtraction Property of Equality

Algebra I

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

Explanation:

Step 1: Define Systems

x + 7y = -2

3x + y = 34

Step 2: Rewrite Systems

x + 7y = -2

1. [Subtraction Property of Equality] Subtract 7y on both sides: x = -2 - 7y

Step 3: Redefine Systems

x = -2 - 7y

3x + y = 34

Step 3: Solve for y

Substitution

1. Substitute in x [2nd Equation]: 3(-2 - 7y) + y = 34
2. [Distributive Property] Distribute 3: -6 - 21y + y = 34
3. [Addition] Combine like terms: -6 - 20y = 34
4. [Addition Property of Equality] Add 6 on both sides: -20y = 40
5. [Division Property of Equality[ Divide -20 on both sides: y = -2

Step 4: Solve for x

1. Substitute in y [1st Equation]: x + 7(-2) = -2
2. Multiply: x - 14 = -2
3. [Addition Property of Equality] Add 14 on both sides: x = 12