Can some find the the answer than explain it Thank you

What number should be added to both sides of the equation to complete this square? x^2-10x=7

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)

What is the slope of any line parallel to the line 8x+9y=3 in the standard (x,y) coordinate plane?