Question 52000
To have no solution, the lines must be parallel, which means they have the same slope.  So first solve both equations for y and you get {{{y=expr(5/4)x-2}}} and {{{y=-expr(10/k)x+11/k}}}.  That means that the slope of the first equation is {{{5/4}}} and for the second it's {{{-expr(10/k)}}}.  Because they must be the same slope for parallel lines, k must have a value of -8.  To verify that, graph both equations to see if they are indeed parallel.
{{{graph(200,200,-5,5,-5,5,5x/4-2,10x/8-11/8)}}}