1/sin^2x-1/tan^2x=
1/sin^2x-1/ (sin^2x/cos^2x)<<sin tan= sin/cos>>
= 1/sin^2x- cos^2x / sin^2x
= (1- cos^2x) / sin^2x <<combining into a single fraction>>
sin^2 x / sin^2x <<since 1- cos^2 x sin^2 x
=1
this simplifies to 1.
Answer:
I think it is the last one
We know how much 16 keychains is, now we need to find how much one is.
19.68 / 16 = $1.23
$1.23 is the price of one keychain, now you can multiply that by 25 to see how much 25 keychains cost.