F(x) varies inversely with x and f(x) = –10 when x = 5. what is the inverse variation equation?
a. f(x)=-2/x
b. f(x)=-50/x
c. f(x)=-0.5/x
d. f(x)=-5/x

What value of x is in the solution set of 4x - 12 s 16 + 8x? -10 -9 -8 -7

Prove (a) cosh2(x) − sinh2(x) = 1 and (b) 1 − tanh 2(x) = sech 2(x). solution (a) cosh2(x) − sinh2(x) = ex + e−x 2 2 − 2 = e2x + 2 + e−2x 4 − = 4 = . (b) we start with the identity proved in part (a): cosh2(x) − sinh2(x) = 1. if we divide both sides by cosh2(x), we get 1 − sinh2(x) cosh2(x) = 1 or 1 − tanh 2(x) = .

Which diagram shows lines that must be parallel lines cut by transversal?