# Toán Lớp 8: Phân tích đa thức thành nhân tử : a) 10x-5xy b) 9x(x-y)-18x+18y c) x^2-7x+6 d) y^2-4x^2+4x-1

Toán Lớp 8: Phân tích đa thức thành nhân tử :
a) 10x-5xy
b) 9x(x-y)-18x+18y
c) x^2-7x+6
d) y^2-4x^2+4x-1

TRẢ LỜI

1. danvanthu
a) $10x$ $-$ $5xy$
$=$ $5x(2-y)$
b) $9x(x-y)$ $-$ $18x$ $+$ $18y$
$=$ $9x(x-y)$ $-$ $18(x-y)$
$=$ $9(x-y)(x-2)$
c) $x^2$ $-$ $7x$ $+$ $6$
$=$ $x^2$ $-$ $6x$ $-$ $x$ $+$ $6$
$=$ $x(x-6)$ $-$ $(x-6)$
$=$ $(x-6)(x-1)$
d) $y^2$ $-$ $4x^2$ $+$ $x$ $-$ $1$
$=$ $y^2$ $-$ $(4x^2$ $-$ $x$ $+$ $1)$
$=$ $y^2$ $-$ $(2x-1)^2$
$=$ $[y-(2x-1)]$$[y+(2x-1)] = (y-2x+1)$$(y+2x-1)$
$Chúc$ $bạn$ $học$ $tốt!$

Trả lời
2. tuenhioanh
Giải đáp:
a, 10x – 5xy
= 5x.(2 – y)
———
b, 9x.(x – y) – 18x + 18y
=  9x.(x – y) – 18.(x – y)
= (9x – 18).(x – y)
= 9.(x – 2).(x- y)
———-
c, x^2 – 7x + 6
= x – 1 – 6x + 6
= (x – 1) – 6.(x – 1)
= (x – 1).(x – 6)
————
d, y^2 – 4x^2 + 4x – 1
= y^2 – (4x^2 – 4x + 1)
= y^2 – [(2x)^2 -2. 2x. 1 + 1^2]
= y^2 – (2x – 1)^2
= [y – (2x – 1)].[y + (2x – 1)]
= (y – 2x + 1).(y + 2x – 1)
#dariana

Trả lời