The equation y= -2x +1 is already in the slope –intercept form. The slope of the line is -2.

The equation -2x +y = 5 can be rewritten in the slope-intercept form as y= 2x +5. The slope of the line is +2

Since the slopes are not same, the lines are not parallel. Also, product of the slopes does not equal to -1, hence the lines are also not perpendicular.

The lines are also not same, as their slopes are different in the first instance

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