A chemist has two solutions of HNO3. One has a 40% concentration and the other has a 25% concentration. How many liters of each solution must be mixed to obtain 126 liters of a 33% solution?

Acircle has a radius of 5/6 units and is centered at (3.6, 7.8) write the equation of this circle

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"

Suppose you are an avid reader and are looking to save money on the cost of books instead of paying about $20 for each book, you decide to look into purchasing a kindle for $120 you can purchase e-books for about $5 each 1. find the slope-intercept equation for the cost of the hard copy of books using x to represent the number of books 2. find the slope-intercept equation for the cost of the kindle with cost of e-books using x to represent the number of books