Answer: Q = 8
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Step-by-step explanation:
The left hand side of the first equation is x-3y
The left hand side of the second equation is 2x-6y = 2(x-3y). Note how it's simply double of the first expression x-3y
If we multiply both sides of the first equation by 2, we get
x-3y = 4
2(x-3y) = 2*4
2x-6y = 8
Meaning that 2x-6y = 8 is equivalent to x-3y = 4. Both produce the same line leading to infinitely many solutions. Each solution will lay along the line x-3y = 4.
We can say each solution is in the set {(x,y): x-3y = 4}
Which is the same as saying each solution is of the form (3y+4,y)