Question 451903
If the equation was equivalent to 0 = 0, this would imply any value for k would work, which does not seem to be the case. Also, be sure to rephrase your question "why does ... equal -1" when you really mean "why does ... have a solution k = -1."


If we cross multiply, we get


2(3-k) = 4(k+3)


-2k + 6 = 4k + 12


-6k = 6


k = -1