Solve the system of equations using substitution or elimination. show work. 3x-4y=-31 x+y=6

Hope this helps I got (-1, 7)

Subtracting is the opposite of adding

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