Which of these is a solution to the system of equations 3x - y = 15 and 6x - 2y = 30?

Solve for y in 3x - y = 15

Solve for y

3x - y = 15

Subtract 3x from both sides

-y = 15 - 3x

Multiply both sides by - 1

y = - 15 + 3x

Regroup terms

y = 3x - 15

Now, substitute y = 3x - 15 into 6x - 2y = 30

Start with the original equation

6x - 2y = 30

Let y = 3x - 15

6x - 2 (3x - 15) = 30

Simplify

30 = 30

Since 30 = 30 is redundant information, this is a dependent system.

There are Infinitely Many Solutions.