By the <u>convention of 3D geometr</u>y, the coordinates of a point (x,y,z) represent how far the point is from the origin forward-backward , right/left , up-down respectively with prior one for the positive coordinate and latter for the negative coordinate.
so we need to move forward 7 for x=7 then to left 6 for y=-6 and then down 5 for z=-5.
10 tacos for 8.49 because 6 tacos for 5.40 it's almost a dollar for each.And the deal 10 tacos for 8.49 you pay more but it's better it's not a dollar for each it's like 84 cents for each