What is the slope-intercept from 6x+y=8

Which shows how to solve the equation 3/4x=6 for x in one step?

How is this equation completed? i cannot find any examples in the book.

Which statement is true about the extreme value of the given quadratic equation? a. the equation has a maximum value with a y-coordinate of -21. b. the equation has a maximum value with a y-coordinate of -27. c. the equation has a minimum value with a y-coordinate of -21. d. the equation has a minimum value with a y-coordinate of -27.