Simpson is solving the systems of equations below by substitution. Show Mr. Simpsons first step if he substitutes the first equation into the second equation. DO SOLVE!

y = 5x + 12

3y + 4x = 150

I’m struggling on this one.

Sketch one cycle if the cosine function y=2cos2theta

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 one is the correct answer, and why?