(Given) 12−5x−4kx=y
(Subtract 12 from both sides) −4kx−5x+12+−12=y+−12
(Simplify) −4kx−5x=y−12
(Factor out variable x) x(−4k−5)=y−12
(Divide both sides by -4k-5) x(−4k−5) / −4k−5 = y−12 / −4k−5
(Answer) x =
Hopefully this is correct, have a nice day! :D