Question

^ - ^

なぜうしろのかっこだけにマイナスをかけるんですか?

(4) (5x)=3x²+(-y-2)x-(2y² + 3y+1)
=3x2+(-y-2)x-(2y+1)(y+1)
=
{3x+(2y+1)}{x-(y+1)}
= (3x+2y+1)(x-y-1)
2
1
3
x
x
2y + 1
-(y+1)
2
1
3
(2y+1Xy+1)
-
1
2
T
1
1 1
3
2y+1
-3y-3
-y-2