Help with my geometry homework please

Which equations represents circles that have a diameter of 12 units and a center that lies on the y-axis? check all that apply

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

Is there a direction u in which the rate of change of f(x, y)equals=x squared minus 3 xy plus 4 y squaredx2−3xy+4y2 at p(1,2) equals 14? give reasons for your answer. choose the correct answer below. a. no. the given rate of change is smaller than the minimum rate of change. b. no. the given rate of change is larger than the maximum rate of change. c. yes. the given rate of change is larger than the minimum rate of change and smaller than the maximum rate of change.