Question

Use the fundamental identities to simplify the expression. There is more than one correct form of the answer.
9sec^2 x (1−sin^2x)

Answer 1

start with the fact that
\[\sin^2(x)+\cos^2(x)=1\] or
\[\cos^2(x)=1-\sin^2(x)\] as your first replacement

Answer 2

get
\[9\sec^2(x)\cos^2(x)\] one more step and you are done

Answer 3

just that the 9 part confused me

Answer 4

ignore it
you get
\[9\frac{1}{\cos^2(x)}\times \cos^2(x)=9\]