Plz help! I need to solve this by today

Find the value of the cosine for angle a

Will give brainliest what is the value of x? enter your answer in the box.

Type the correct answer in the box. consider the system of linear equations below. rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.