No idea what I'm doing please help

Gretchen is setting up for a banquet. she has 300 chairs and needs to distribute them evenly among t tables. how many chairs should she put at each table? write your answer as an expression.

3-12. write each answer with a reasonable number of figures. find the absolute uncertainty and percent relative uncertainty for each answer. (a) [12.41 (±0.09) + 4.16 (±0.01)] x 7.068 2 (±0.000 4) =? (b) [3.26 (±0.10) x 8.47 (±0.05)] - 0.18 (±0.06) =? (c) 6.843 (±0.008) x 104 + [2.09 (±0.04)- 1.63 (±0.01)] =?

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10