Make y the subject of the equation: t=(y+2)/(4-y)

Multiply by 4-y   => t(4-y)=y+2 Expand the brackets  => 4t-ty=y+2 Get all the y's on the same side => 4t-2=ty+y Factor out the y  => 4t-2=(t+1)y Divide by t+1  => (4t-2)/(t+1)=y