Question

Solve by substitution x-7y=7 6x-7y=-28

Answer 1

Answer:

(-7, -2)

General Formulas and Concepts:

Pre-Algebra

• Order of Operations: BPEMDAS
• Equality Properties

Algebra I

• Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define systems

x - 7y = 7

6x - 7y = -28

Step 2: Rewrite systems

x = 7y + 7

6x - 7y = -28

Step 3: Solve for y

1. Substitute:                              6(7y + 7) - 7y = -28
2. Distribute 6:                            42y + 42 - 7y = -28
3. Combine like terms:              35y + 42 = -28
4. Isolate y term:                        35y = -70
5. Isolate y:                                 y = -2

Step 4: Solve for x

1. Define original equation:          x - 7y = 7
2. Substitute in y:                           x - 7(-2) = 7
3. Multiply:                                      x + 14 = 7
4. Isolate x:                                     x = -7

And we have our answer!