Vineet wants to polish the floor of a room which is 140 cm long and 120 cm wide. The charges for polishing the floor is 52 per square metre. What will be the cost of
polishing the floor of the room?​

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

Gravel is being dumped from a conveyor belt at a rate of 25 ft3/min, and its coarseness is such that it forms a pile in the shape of a cone whose base diameter and height are always equal. how fast is the height of the pile increasing when the pile is 14 ft high? (round your answer to two decimal places.) ft/min

How is this equation completed? i cannot find any examples in the book.