What is −y+9z−16y−25z+4 written in simplest form?

Steve wants to develop a way to find the total cost of any item including sales tax. the sales tax in his city is 6%. his friend jenna writes the expression x + 6x where x is the cost of the item. explain whether her expression is correct based on the situation.

Given a: b and b: c, find a: b: c. write the ratio in simplest form. a: b=6: 10 and b: c=21: 33

Ateacher wanted to buy a chair, a bookshelf, two tables and a desk. she spent $900 for all five items and the chair and the desk combined 70% of her total. if the bookshelf cost $50, how much did each of the tables cost?