Question

HELP PLEASE!⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀

Answer 1

He messed up in the beginning with the 4.

It's supposed to be
(3 - -4)
(3 + 4)

and not

(3-4)

That's where he messed up.




I find it interesting how he uses Xa Ya and Xb Yb. In my school we use X1 Y1 and X2 Y2.