How do you solve ky-bf=fy/m?

Which variable would you like to solve for?

Let's try solving for y since you have two of them.

ky - bf = fy/m

kym - bfm = fy - - > [ multiply by m ]

kym - fy = bfm - - > [ subtract fy on both sides ]

y (km-f) = bfm - - - > [ factor out a y ]

y = bfm / (km-f) - - - > [ divide by km-f on both sides ]