An environmental scientist obtains a sample of water from an irrigation canal that contains a certain type of bacteria at a concentration of 8 per milliliter. Fine the mean number of bacteria in a 5 milliliter sample

correct answer:

b.(19,-2)

x= cost per bracelet

number of bracelets * x + shipping charge = total cost

so

9x+9=72

let's first notice, the center of the hyperbola is at the origin, since the focus points are equidistantly 3 units away from the origin, that also means that the distance "c" from the center to either focus is 3.

it should also be notable that, the traverse axis for this hyperbola is vertical, or namely over the y-axis and therefore, the positive fraction will be the one with y-variable.

the traverse "a" component or distance from the center to either vertex is not 2, is more than 2, so we can safely put it at √5 ≈ 2.24.