Which property was used to manipulate the following expression?
(a + b)(c + d) = (c+d) (a+b)

Which is the equation of an ellipse with directrices at x = ±4 and foci at (2, 0) and (−2, 0)?

Jackie purchased 3 bottles of water and 2 cups of coffee for a family for $7.35. brian bought 4 bottles of water and 1 cup of coffee for his family for $7.15. how much does each bottle of water cost? how much does each cup of coffee cost? i need this done

Acar travels at an average speed of 56 miles per hour. how long does it take to travel 196 miles