Question

Explain why the two equations below have the same solutions. x + 3y = −1 −2x − 6y = 2

Answer 1

x + 3y= -1
-2x - 6y = 2

These two equations have the same solution because we can see that they are equivalent. 

One way to find out is this:-

Since x has a +1 next to it, and the other equation has a (-2) next to the x, we can multiply everything on the first equation by 2 to see if they are equivalent.

x+3y= -1
(-2)*x + 3y*-2 = -1*-2
-2x+ (-6y) = 2
-2x-6y=2

Now we know that both of these equations have the same solution.