A skin-care company had 1,500 people try a new acne cream. Nine people had a mild allergic reaction. The formula is then improved and those 1,500 people try the new cream. Only 4 of them had a mild allergic reaction. What is the percent decrease in number of allergic reactions?

idk

step-by-step explanation:

do it yourself, cause that made me do it myself today, in english!

answer:

your answer is: c. 196 7/8 in^3.

we have three similar triangles, because each has a right angle and shares an angle.   let's write the angles in order: opposite to short leg, long leg, hypotenuse.

cab similar to bad similar to cbd

or as ratios,

ca: ab: cb = ba: ad: bd = cb: bd: cd

we also know

ac = ad + cd

(ad+cd): ab: cb = ba: ad: bd = cb: bd: cd

(ad+cd)/cb=cb/cd

we have cb=6, ad=5 and seek x=cd.

we reject the negative root and conclude x=4

answer: 4

or

step-by-step explanation:

we need to solve for 'x' the following equation:  

we have that:

⇒

⇒ ⇒

factorizing, we get that:

  ⇒

then, the solutions are: or

nothing extraneous has been found!