I need help on c and d

Triangle abc is reflected over the line y=x triangle abc has points (-6,-,-1) and (-5,-6) what is the c coordinate

Liz is shipping a package to her friend. the maximum weight of a medium flat-rate box is 20 pounds, including the box which weighs 6 ounces. write and solve an inequality to describe the possible weight ,w, of the contents that liz will ship to her friend if she must use a medium flat-rate box.

Which value of m will create a system of parallel lines with no solution? y= mx - 6 8x - 4y = 12