If u is a square matrix such that u^tu = i what can we say about det(u)

The weekly revenue for a company is r = 3p^2 + 60p + 1060, where p is the price of the company's product. what price will result in a revenue of $1200.

Serena is making an experiment. for that, she needs 20 grams of a 52% solution of salt. she has two large bottles of salt water: one with 40% and the other with 70% of salt in them. how much of each must she use to make the solution she needs? i am in need of

Bc and bd are opposite rays. all of the following are true except a)a,b,c,d are collinear b)a,b,c,d are coplanar c)bc=bd d)b is between c and d