Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a,(a-1)(a-2)+(a-3)(a-4)-(2a^2+5a+34)
=a2-3a+2+a2-7a+12-2a2-5a-34
=-15a-20
sai đề kakakakakaka
b, (a-b)(a^2+ab+b^2)-(a+b)(a^2+ab+b^2)
=a3-b3-(a3+b3)
=a3-b3-a3-b3
=-2b3
1, \(2\left(x+y\right)-5a\left(x+y\right)=\left(x+y\right)\left(2-5a\right)\)
2, \(a^2\left(x-5\right)-3\left(x-5\right)=\left(a^2-3\right)\left(x-5\right)\)
3, \(4x\left(a-b\right)+6xy\left(b-a\right)=\left(4x-6xy\right)\left(a-b\right)=2x\left(2-3y\right)\left(a-b\right)\)
4, \(y\left(a-b\right)-x\left(b-a\right)=\left(x+y\right)\left(a-b\right)\)
5, \(6x\left(x-y\right)+8y\left(y-x\right)=\left(x-y\right)\left(6x-8y\right)=2\left(3x-4y\right)\left(x-y\right)\)
6, \(4\left(x-3\right)^2-2x\left(x-3\right)=\left(x-3\right)\left[4\left(x-3\right)-2x\right]=2\left(x-3\right)\left(x-6\right)\)
Ta có T = (x + 2)(x + 3)(x + 4)(x + 5) – 24
= [(x + 2)(x + 5)].[(x + 3)(x + 4)] – 24
= ( x 2 + 7x + 10).( x 2 + 7x + 12) – 24
Đặt x 2 + 7x + 11= t, ta được
T = (t – 1)(t + 1) – 24 = t 2 – 1 – 24 = t 2 – 25 = (t – 5)(t + 5)
Thay t = x 2 + 7x + 11, ta được
T = (t – 5)(t + 5) = ( x 2 + 7x + 11 – 5)( x 2 + 7x + 11 + 5)
= ( x 2 + 7x + 6)( x 2 + 7x + 16)
Suy ra a = 6; b = 16 => a – b = -10
Đáp án cần chọn là: D
1, 5a2xy-10a3x-15ay = 5a( axy - 2a\(^2\)x - 3y )
2, mxy-m2x+my = m( xy - mx + y )
3, 2mx-4m2xy+6mx = 2mx( 1 - 2my + 3 ) = 2mx( 4 - 2my )
4, a2b-2ab2+ab = ab( a - 2b + 1 )
5, 5a2b-2ab2+ab = ab( 5a - 2b +1 )
6, -3x2y3-6x3y2-x2y2 = -3x\(^2\)y\(^2\) ( y + 2x + 1 )
7, 5x2y4-10x4y2+5x2y2 = 5x\(^{^2y^2}\)( y\(^2\) - 2x\(^2\) + 1 )
8, -2x3y4-4x4y3+2x3y3 = 2\(x^3y^3\) ( -y - 2x + 1 )
9, 4x3y2-8x3y+16xy2-24 = 4( x\(^3\)y\(^2\) - 2x\(^3\)y + 4 xy\(^2\) - 6 )
10, 12x3y-6xy+3x = 3x( 4x\(^2\)y - 2y + 1 )
11, 2(x-y)-a(x-y) = ( 2 - a ) ( x - y )
12, a(x-y)+b(x-y)= ( a + b ) ( x - y )
13, m(x+y)-n(x+y) = ( m - n ) ( x + y )
14, 2a(x+y)-4(x+y) = ( 2a - 4 )( x + y ) = 2( a - 2 ) ( x + y )
15, 3a(x+y)-6ab(x+y) = ( 3a - 6ab )( x + y ) = 3a( 1 - 2b ) ( x + y )
16, 5a2(x-y)+10a(x-y) = ( 5a\(^2\)+10a )( x - y ) = 5a( a + 2 ) ( x - y )
17, -2ab(x-y)-4a(x-y) = ( -2ab - 4a )( x - y ) = -2a( b + 2 )( x - y )
18, 3a(x-y)+2(x-y) = ( 3a + 2 ) ( x - y )
19, m(a-b)-m2(a-b) = ( m - m\(^2\) ) ( a - b ) = m( 1 - m ) ( a - b )
20, mx(a+b)-m(a+b) = ( mx - m ) ( a + b ) = m( x - 1 )( a + b )
21, x(a-b)-y(b-a) = x( a - b ) + y( a - b ) = ( x + y ) ( a - b )
22, ab(x-5)-a2(5-x) = ab( x - 5 ) + a\(^2\)( x - 5 ) = ( ab + a\(^2\) ) ( x - 5 ) = a( b + a )( x - 5 )
23, 2a2(x-y)-4a(y-x)= 2a\(^2\)( x - y ) + 4a( x - y )=( 2a\(^2\) + 4a ) ( x - y )= 2a( a + 2 )( x - y )
Đăng ít thôi =))
a. \(5a^2xy-10a^3x-15ay=5a\left(axy-2a^2x-3y\right)\)
b. \(mxy-m^2x+my=m\left(xy-mx+y\right)\)
c. \(2mx-4m^2xy+6mx=2mx\left(1-2my+3\right)=2mx\left(-2my+4\right)\)
d. \(a^2b-2ab^2+ab=ab\left(a-2b+1\right)\)
e. \(5a^2b-2ab^2+ab=ab\left(5a-2b+1\right)\)
g.
ko biết
Sai bét.