Question 156170
Using the orinal set of numbers gives you the equation you want: 
y = 0.2x + 156
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Making the 50 becomes 0 change sinply
moved the regression line 10 to the left.
The y-value for 50 in the 1st set and 0
in the 2nd set are the same because you
only translated the x values.
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Each of your sets of x/y pairs gives rise
to a different regression line.  I don't
know who told you to traslate 50 to 0;
you might ask them, why?
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Cheers,
Stan H.