Question 134032
There is no solution for b. This is becuase the two equations listed in B are, in fact the same equation.
{{{x - 2y = -6}}}
{{{x = 2y - 6}}} multiply by 2
{{{2x = 4y - 12}}}

Which is the second equation given. There are two variables and only one eqaution, so you can't solve this one.