Phân tích đa thức thành nhân tử: a) a² – 2ab + a – 2a b) 2(x – 7) + x – 7 c) x(x – 3) – x + 3 d) x² – 2xy + y² – 16 02/12/2021 Bởi Harper Phân tích đa thức thành nhân tử: a) a² – 2ab + a – 2a b) 2(x – 7) + x – 7 c) x(x – 3) – x + 3 d) x² – 2xy + y² – 16
`a,a^2-2ab+a-2a` `=(a^2-2ab)+(a-2a)` `=a(a-2b)-a` `=a(a-2b-1)` `b,2(x-7)+x-7` `=(x-7)(2+1)` `=3(x-7)` `c,x(x-3)-x+3` `=x(x-3)-(x-3)` `=(x-3)(x-1)` `d,x^2-2xy+y^2-16` `=(x^2-2xy+y^2)-16` `=(x-y)^2-4^2` `=(x-y+4)(x-y-4)` Bình luận
a) $a^2-2ab+a-2a$ $=a.(a-2b-1)$ b) $2(x-7)+x-7$ $=(x-y)(2+1)$ $=3(x-y)$ c) $x(x-3)-x+3$ $=x(x-3)-(x-3)$ $=(x-3)(x-1)$ d) $x^2-2xy+y^2-16$ $=(x-y)^2-16$ $=(x-y-4)(x-y+4)$ Bình luận
`a,a^2-2ab+a-2a`
`=(a^2-2ab)+(a-2a)`
`=a(a-2b)-a`
`=a(a-2b-1)`
`b,2(x-7)+x-7`
`=(x-7)(2+1)`
`=3(x-7)`
`c,x(x-3)-x+3`
`=x(x-3)-(x-3)`
`=(x-3)(x-1)`
`d,x^2-2xy+y^2-16`
`=(x^2-2xy+y^2)-16`
`=(x-y)^2-4^2`
`=(x-y+4)(x-y-4)`
a) $a^2-2ab+a-2a$
$=a.(a-2b-1)$
b) $2(x-7)+x-7$
$=(x-y)(2+1)$
$=3(x-y)$
c) $x(x-3)-x+3$
$=x(x-3)-(x-3)$
$=(x-3)(x-1)$
d) $x^2-2xy+y^2-16$
$=(x-y)^2-16$
$=(x-y-4)(x-y+4)$