Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) ( x 2 – 4x + 1)( x 2 – 2x + 3).
b) ( x 2 + 5x – 1)( x 2 + x – 1).
Ta có: x2y+5xy-14y
= y(x2+5x-14)
= y(x+7)(x-2)
x3-5x2-14x
= x(x2-5x-14)
= x(x-7)(x+2)
\(x^2y+5xy-14y\)
\(=x^2y-2xy+7xy-14y\)
\(=xy\left(x-2\right)+7y\left(x-2\right)\)
\(=\left(x-2\right)\left(xy+7y\right)\)
\(x^3-5x^2-14x\)
\(=x^3-7x^2+2x^2-14x\)
\(=x^2\left(x-7\right)+2x\left(x-7\right)\)
\(=\left(x^2+2x\right)\left(x-7\right)\)
\(=x\left(x+2\right)\left(x-7\right)\)
Bài làm
3x2 + 14x - 15
= 3x2 + 9x + 5x - 15
= -( 9x - 3x2 ) - ( 15 - 5x )
= -3x( 3 - x ) - 5( 3 - x )
= ( 3 - x )( -5 - 3x )
# Hokc tốt #
7x2+15x-5=0
7*(x2+2.5x-5/7)=0
x2+2*x*1.25+1,5625-255/112=0
(x+1.25)2-255/112=0
\(x^4-6x^3+12x^2-14x+3\)
= \(x^4-4x^3+x^2-2x^3+8x^2-2x+3x^2-12x+3\)
= \(x^2\left(x^2-4x+1\right)-2x\left(x^2-4x+1\right)+3\left(x^2-4x+1\right)\)
= \(\left(x^2-4x+1\right)\left(x^2-2x+3\right)\)
= \(5x^3-2x^2-10x^2+4x+10x-4\)
= \(5x^2\left(x-\frac{2}{5}\right)-10x\left(x-\frac{2}{5}\right)+10\left(x-\frac{2}{5}\right)\)
=\(\left(x-\frac{2}{5}\right)\left(5x^2-10x+10\right)\)
Chuc ban hoc tot!
Trả lời:
7x2 - 7y2 - 14x + 14y
= 7 ( x2 - y2 - 2x + 2y )
= 7 [ ( x2 - y2 ) - ( 2x - 2y ) ]
= 7 [ ( x - y )( x + y ) - 2 ( x - y ) ]
= 7 ( x - y )( x + y - 2 )