Solve each equation check your solution. 2/7y + 5 = -9

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

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?