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However, it appears as if the two equations are essentially the same and therefore there are infinitely many solutions.
If you mean y = 2x then it is a straight line equation
y2x - just double the coordinate of y to get x. xy12 - i have no idea
If you mean: y = 2x+5 then it is a straight line equation.
If you mean: y = 2x-4 then it is equal to a straight line equation
No because it's not a simultaneous equation but some kind of algebraic expression
Without a second independent equation, it's not a 'system' yet.
If you mean y = 2x-3 then the parallel equation will have the same slope of 2 but with a different y intercept
If you mean: y = 2x-4 and (1, 5) then the parallel equation is y = 2x+3
As written this is not a graphable thing. I does not represent a graphable equation because there is no "=" sign. Whatever the equation might be, the x intercept is found by setting y=0, which leaves you with an equation for x, which is the intercept.
If you mean: y = 2x-3 then the slope is 2 and the y intercept is -3
If you mean y = 2x-3 then it is a straight line equation whereas 2 is the slope and -3 is the y intercept