Can someone help me figure out the 2 proofs for questions 1 and 3 and help me find what X and Y equal for question 2 if you can!! In geometry

Express the following as a function of a single angle, cos(60) cos(-20) - sin(60) sin(-20)

The angle of a triangle are given as 6x,(x-3), and (3x+7). find x then find the measures of the angles

Raj encoded a secret phrase using matrix multiplication. using a = 1, b = 2, c = 3, and so on, he multiplied the clear text code for each letter by the matrix to get a matrix that represents the encoded text. the matrix representing the encoded text is . what is the secret phrase? determine the location of spaces after you decode the text. yummy is the corn the tomato is red the corn is yummy red is the tomato