Question 314481
{{{2x -y = 3}}} double this
{{{4x - 2y = 6}}}
{{{4x + ky = 4}}} subtract this equation from the one above
{{{(-2 -k)y = 2}}}
{{{y = -2/(2+k)}}}
if k = -2, then the denominator is 0. And so is undefined. Implies no solution

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{{{2x - y = 3}}} double this
{{{4x - 2y = 6}}}
{{{4x -2y = 4}}}
This cannot be true, since 6 does not equal 4