Choose the best initial step in solving the following system by substitution 3x+6y=7 and 2x+8y=14 B. Solve the first equation for y. C. Solve the second equation for x. D. Solve the second equation for y.

Evaluate the expression. (9 + 5)(3 + 2)0

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) = .

Michael is training for a marathon. in his first week he plans to run 8miles. what path should he take