How can you evaluate an algebraic expression

Can you me find the missing length. i attached an image.

Identify the expression equivalent to 4(x + x + 7) − 2x + 8 − 4 by substituting x = 1 and x = 2.

The correlation coefficient between the number of students and marks obtained in end semester exam. (13 marks) give the statistical meaning of the relationship between the number of students and marks b. obtained in end semester exam. (3 marks) draw the number of students and marks obtained in end semester exam scatter diagram c. (4 marks) check list write your name and id corectly write the question number properly use your own calculator. show all the steps to solve the problems. use the correct formula. answer in provided time. don't use your mobile for any purpose. write your answer up to two decimal places