Look at this picture and answer plz i already got the first part i just need the rest also tell me if the first part is correct Or not

Which expression gives the area of the triangle shown below

Graph the system of inequalities presented here on your own paper, then use your graph to answer the following questions: y < 4x − 8 y is greater than or equal to negative 5 over 2 times x plus 5 part a: describe the graph of the system, including shading and the types of lines graphed. provide a description of the solution area. (6 points) part b: is the point (5, −8) included in the solution area for the system? justify your answer mathematically. (4 points)

Idon't get undoing if its pass adding and subtracting so can someone ? x-2 over 5 = 18