X+1/x+10 * (x+10) (x-6) / (x-6) (x-1) multiply

x+1/x+10 * (x+10) (x-6) / (x-6) (x-1) 
= x+1/x+10 * (x+10) / (x-1) 
= (x+10) (x+1) / (x+10) (x-1)
= (x+1) / (x-1) 

If you need an equation, it would be y=2x+8, y would be how long it grew, x being weeks.if you need how long he was asleep, it would be 4 weeks if he started with no beard, the equation would be x=8÷2if he did have a beard before hand, the equation would be 2w+x=8

With a continuous thought process.