Intercepts of 9x^2+9y=81

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

Which of the following represents a number squared is equal to twenty more than nine times that number ? a) x squared = 9x + 20 b) x squared = 20x + 9 c) x squared > 9 + 20x d) x squared = 9 + x + 20

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.