Answer: -3
Step-by-step explanation: substitute y and x into the formula y=k/x, and that is 4=k/-12. Then you multiply the -12 over, you get that k=-48. Then you substitute that into the same equation getting y=-48/x, but then you see that y should be 16, so then it would be 16=-48/x. Then, you flip the two fractions to make it more simpler looking like 1/16=x/-48x. Then you multiply the -48 over, getting x=-3.
