What is the surface area of a square with a height of 7 the width of 7 and the length of 12

Ten times the square of a non-zero number is eqaul to ninety times the number

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g

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?