Answer :
k in (-oo:+oo)
3/2 = (9/10)*k // - (9/10)*k
3/2-((9/10)*k) = 0
(-9/10)*k+3/2 = 0
3/2-9/10*k = 0 // - 3/2
-9/10*k = -3/2 // : -9/10
k = -3/2/(-9/10)
k = 5/3
k = 5/3
this is the answer
3/2 = (9/10)*k // - (9/10)*k
3/2-((9/10)*k) = 0
(-9/10)*k+3/2 = 0
3/2-9/10*k = 0 // - 3/2
-9/10*k = -3/2 // : -9/10
k = -3/2/(-9/10)
k = 5/3
k = 5/3
this is the answer