If 20 kisses and 5 hugs cost $11.50 and 3 kisses and 10 hugs cost $4.50. how much does one kiss cost?

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

Using the figure below, select the two pairs of alternate interior angles.a: point 1 and point 4 b : point 2 and point 3 c: point 6 and point 6d: point 5 and point 7

Ibeg you to me 20. a reaction produces 4.93 l of oxygen, but was supposed to produce 1 mol of oxygen. what is the percent yield?