Can anyone help in question 18a?

Nnnnneeedd 1.find the residual if you know the actual number is 5.2 and the predicted value is 4.8

In what form is the following linear equation written y=9x+2

Solve the problem. a student earned grades of c, a, b, and a in four different courses. those courses had these corresponding numbers of credit hours: 4, 5, 1, and 5. the grading system assigns quality points to letter grades as follows: a = 4, b = 3, c = 2, d = 1, and f = 0. compute the grade point average (gpa) and round the result to two decimal places. 3.40 3.50 8.75 2.18