Acosmetics company tested a new lotion. of the 2,500 people tested, 15 had an allergic reaction. what percent of the people tested had an allergic reaction to the new lotion

If we want to know what percent of a number A is of another number B, then all we have to do is to simply divide number A by number B. Then either we move the decimal place of the answer two places to the right or multiply the answer with 100, either method results in the same number.

So the percent of tested people who had an allergic reaction to the new lotion is:

percent people = (15 / 200) * 100

percent people = 0.075 * 100

 percent people = 7.5%

Therefore 7.5% of the people had allergic reaction.

if the eqn of the parabola is f(x) = (x-4)(x+2), we need to mult. this out to find the coordinates of the vertex.

then f(x) = x^2 + 2x - 4x - 8, and f(x) = x^2 - 2x - 8.

one way in which you can find the vertex is to calculate x = -b / (2a).   here, that comes to

        )

x = = 1.   f(1) = 1^2 - 2(1) - 8 = - 9.   vertex is at (1, -9).

        2(1) 

find another point on the curve:   let x=0, for which y=-8.   then (0, -8) is on the curve.   plot the vertex and this point and draw a smooth parabola thru both.

hope this