X= y - 3
x + 3y = 13

what is the solution to the system of equations?
a) (1, 4)
b) (4, 1)
c) (7, 4)
d) (2.5, 5.5)

Ihave trouble finding the nth term of a linear sequence

If i have 20$ and i gave 5$ away how much i got

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) = .