An octagon has three equal angles each of measure $115^{\circ}$ If all the remaining angles have equal measure, find the measure of each of these remaining angles.
The angles of a heptagon are $(x+3)^{\circ},(2 x+5)^{\circ},(x+8)^{\circ},(3 x+1)^{\circ},(5 x-6)^{\circ}$, $(2 x+9)^{\circ}$ and $(x-5)^{\circ}$. Calculate $x$.