BT1: Tính a.2y(3y3 +4y-18) b.(3y+x)(x-3y) c.(-4+x)2 BT 2: Phân tích đa thức thành nhân tử a.9y3 x -36y2 x b.64-y2 -x2 +2xy c.x2 +x-30
Có gì bạn sửa nhen
BT1: Tính a.2y(3y3 +4y-18) $=2y.3y^3+2y.4y-2y.18$ $=6y^4 +8y^2 -36 y$
$=2y.3y^3+2y.4y-2y.18$
$=6y^4 +8y^2 -36 y$
b.(3y+x)(x-3y) $=(x+3y)(x-3y)$ $=x^2 -(3y)^2 $ $=x^2 -9y ^2 $
$=(x+3y)(x-3y)$
$=x^2 -(3y)^2 $
$=x^2 -9y ^2 $
c.(-4+x)2 $=(x-4)^2$ $=x^2 -8x+16$
$=(x-4)^2$
$=x^2 -8x+16$
1) a.2y(3y3 +4y-18) =2y.3y3 +2y.4y-2y.18 =6y4 +8y2 -36 y b.(3y+x)(x-3y) =(x+3y)(x-3y)=(x+3y)(x−3y) =x2 -(3y)2 =x2 -9y 2 c.(-4+x)2 =(x-4) =x2 -8x+16 2) a.9y3 - 36y2 x =9y2 x (y-4) b.64-y2 -x2 +2xy =82 -(y2 -2xy+x2) =82 -(y-x)2 =(8-y+x)(8+x-y) c. x2 +x-30 =x2 +6x-5x-30 =(x2 +6x)-(5x+30) =x(x+6)-5(x+6) =(x+6)(x-5)
