F. (10 pts) An important concern in the study of heat transfer is to determine the steady-state temperature distribution of a thin plate when the temperature around the boundary is known. Assume the plate shown in the figure represents a cross-section of a metal beam, with negligible heat flow in the direction purpendicular to the plate. Let T1,T2,T3, and T4 denote the temperatures at the four interior nodes of the mesh in the figure. The temperature at a node is approximately equal to the average of the four nearest nodes - to the left, above, to the right, and below. For instance, T1=(5+20+T2+T4)/4or4T1T2T4=25 Write a system of four equations whose solution gives estimates for the temperatures T1,,T4