skąd ta 1 i -3 zamiast A i B ?

matematykaszkolna.pl

skąd ta 1 i -3 zamiast A i B ? pan szarik:

−2x+5		−2x+5		A		B
	=		=		+		=
x²+x−2		(x−1)(x+2)		x−1		x+2

	1		−3		3x
=		+		=
	x−1		x+2		x³ +1

13 lis 18:58

irena:

−2x+5		A		B		A(x+2)+B(x−1)
	=		+		=		=
(x−1)(x+2)		x−1		x+2		(x−1)(x+2)

	Ax+2A+Bx−B		(A+B)x+(2A−B)
=		=
	(x−1)(x+2)		(x−1)(x+2)

(A+B)x+(2A−B)=−2x+5

⎧	A+B=−2
⎩	2A−B=5

3A=3 A=1 1+B=−2 B=−3

−2x+5		1		−3
	=		+
(x−1)x+2)		x−1		x+2

13 lis 19:52