Aydin shaded number in the addition table which statement tells what shaded number show

Which value of c would make he following expression completely factored? 8x+cy

Plz ( true - false) all triangles have interior angles whose measure sum to 90.

Will mark 50 show all what is the solution to the system of equations? use the substitution method and show your work. -5x+y= -3 -15 x+3y=7 explain what your answer in part (a) tells you about the association of the lines in this system.