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

(-7, -2)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDASEquality 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

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

Step 4: Solve for x

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

And we have our answer!