no number can have a positive and a negative at the same time. a negative number has a negative sign and a positive number has a plus sign.
<span>-1/4y(2y^3 - 8)
= -1/2 y^4 + 2 y</span>
(1,3) and (7,3) falls on the same horizontal line. hence, the distance is just equal to 6 units. (7,3) and (7,7) meanwhile lie on the same vertical line. hence the distance is 4. (7,7) and (4,7) lie on the same horizontal line with a distance of 3.
Finally, to get back to point (1,3) - (4,7) ----> (1,3), 3 to the left and 4 down, the diagonal being 5.
6+4+3+5= 10 + 8 = 18.