If you can’t answer this may you explain plz (added photo)

Draw a tape diagram to represent each situation.for some of the situations,you need to decide what to represent with a variable andre bakes 9 pans of brownies.he donates 7 pans to the school bake sale and keeps the rest to divide equally among his class of 30 students

Someone answer this check out the image!

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*