I'm in desperate need of trig help...

Which is the graph of this function 3 square root of x plus one if

The difference of three and the reciprocal of a number is equal to the quotient of 20 and the number. find the number.

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?