6x – 8y – 5х + Зу
what is the answer

This is so hard and it’s for a test

Which equation can be used to measure the density of water in a spherical water tank? let w represent the number of water particles within the region.

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.