Which of the following is equal to the expression below ? (6^-7 ) ^3
a. (-1/6) ^21
b. (1/6 ) ^21
c. (1/6) ^-21
d. (-1/6 ) ^-21 ?

Plz me plz i need and plz delte this after answer

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) = .

Maurice has 54 fewer comic books than rebecca. they have 130 comic books together .how many comic books are in maurices collection ? how many comic books are in rebeccas collection