. Mark drove 180 miles in 3 hours at a constant speed. Let D equal the
distance traveled and t equal the time
traveled. Which of the following is
the constant of proportionality?

A) 3, as in D=3t

B) 60, as in D=60t

C) 180, as in D=180t

D) 540, as in D=540t

Simplify.7x + 3y - 2 + 6x + 1 + y squared 2 you! ; )

If x=-3 is the only x-intercept of the graph of a quadratic equation, which statement best discribes the discriminant of the equation?

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) = .