The sum of nine and one times a number is 21. what is the number?

Pls if a cow has a mass of 9×10^2 kilograms, and a blue whale has a mass of 1.8×10^5 kilograms, which of these statements is true?

For each polynomial, determine the degree and write the polynomial in descending order. a. –4x^2 – 12 + 11x^4 b. 2x^5 + 14 – 3x^4 + 7x + 3x^3

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) = .