PL HELPWhich is the equation of a hyperbola with directrices at x = ±3 and foci at (4, 0) and (−4, 0)? x squared over 16 minus y squared over 4 equals 1 x squared over 12 minus y squared over 4 equals 1 y squared over 16 minus x squared over 4 equals 1 y squared over 12 minus x squared over 4 equals 1

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)