I have a quick question on what i have to do. pls help. Do i have to add or subtract those?

Anne is twice as old as bill, and bill is 3 years older than christie. the sum of anne s and christie s ages equal 72. find their age difference.?

Lorne subtracted 6x3 – 2x + 3 from –3x3 + 5x2 + 4x – 7. use the drop-down menus to identify the steps lorne used to find the difference.

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8