Add a sign 3 6 4 2 0=7,280? what sign would i add? im confused

To get the answer of 7,280 all i can figure out is to multiply (X) 364 x 20 = 7,280 and that gives you the answer you show of 7,280.

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