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x4+7x3+14x2+14x+4
=x4+7x3+4x2+10x2+14x+4
=(x4+4x2+4)+(7x3+14x)+10x2
=(x2+2)2+7x(x2+2)+10x2
=(x2+2)2+2x(x2+2)+5x(x2+2)+10x2
=(x2+2)(x2+2+2x)+5x(x2+2+2x)
=(x2+2+2x)(x2+2+5x)
á,(x+7)2-y2
= (x+7+y)(x+7-y)
b, (x+1)(x-25)
chúc bạn luôn thành công trong cuộc sống nha
a)
\(x^2-y^2+14x+49\)
\(=\left(x^2+14x+49\right)-y^2\)
\(=\left(x^2+2.7.x+7^2\right)-y^2\)
\(=\left(x+7\right)^2-y^2\)
\(=\left(x+y+7\right)\left(x-y+7\right)\)
Vậy ...
x3 + x2 + 4
= x3 + 2x2 - x2 - 2x + 2x + 4
= x2(x + 2) - x(x + 2) + 2(x + 2)
= (x + 2)(x2 - x + 2)
2x3 - 3x2 + 3x - 1
= 2x3 - x2 - 2x2 + x + 2x - 1
= 2x2(x - 1/2) - 2x(x - 1/2) + 2(x - 1/2)
= (x - 1/2)(2x2 - 2x + 2)
= 2(x - 1/2)(x2 - x + 1)
3x3 - 14x2 + 4x + 3
= 3x3 + x2 - 15x2 - 5x + 9x + 3
= 3x2(x + 1/3) - 15x(x + 1/3) + 9(x + 1/3)
= (x + 1/3)(3x2 - 15x + 9)
= 3(x + 1/3)(x2 - 5x + 3)
x4+2.x3-13.x2-14x+24
=x3.(x+2)-13x2+12x-26x+24
=x3.(x+2)-x.(13x-12)-2.(13x-12)
=x3.(x+2)-(13x-12)(x+2)
=(x+2)(x3-13x+12)
=(x+2)(x3-x-12x+12)
=(x+2)[x.(x2-1)-12.(x-1)]
=(x+2)[x.(x-1)(x+1)-12.(x-1)]
=(x+2)(x-1)[x.(x+1)-12]
=(x+2)(x-1)(x2+x-12)
=(x+2)(x-1)(x2-3x+4x-12)
=(x+2)(x-1)[x.(x-3)+4.(x-3)]
=(x+2)(x-1)(x-3)(x+4)
1.2x^2+x-6=2x^2+4x-3x+6=(2x^2+4x)-(3x+6)=2x(x+2)-3(x+2)=(x+2)(2x-3)
2.x^3-9x^2+14x
=x*(x^2-9x+14)
=x*(x^2-7x-2x+14)
=x*((x^2-7x)-(2x-14))
=x*(x(x-7)-2(x-7))
=x*((x--7)(x-2))
=x*(x-7)(x-2)
1)
\(=\left(x-7\right)^2-4a^2\)
\(=\left(x-7+2a\right)\left(x-7-2a\right)\)
2)
\(=\left(3x+1\right)^2-5^2\)
\(=\left(3x+1+5\right)\left(3x+1-5\right)\)
\(=\left(3x+6\right)\left(3x-4\right)\)
\(=3\left(x+2\right)\left(3x-4\right)\)
1)x^2-14x+49-4a^2
=x^2-2x7+7^2-4a^2
=\(\left(x-7\right)^2-4a^2\)
=\(\left(x-7\right)^2-\left(2a\right)^2\)
=\(\left(\left(x-7\right)-\left(2a\right)\right).\left(\left(x-7\right)+\left(2a\right)\right)\)
=\(\left(x-7-2a\right).\left(x-7+2a\right)\)
b)
\(9x^2+6x+1-25\\ =\left(3x\right)^2-5^2+6x+1\\ =\left(\left(3x\right)-5\right).\left(\left(3x\right)+5\right)+6x+1\)
\(=\left(3x-5\right).\left(3x+5\right)+6x+1\)
cái này có những biểu thức ko dùng được hđt hoặc đặt nhân tử chung =))) anh nghĩ đề em nên thay chữ và thành hoặc
1, \(15x^2+10xy=5x\left(3x+2y\right)\)
2, \(24x-18y+30=6\left(4x-3y+5\right)\)
3, \(2x\left(y-2009\right)+5y\left(y-2009\right)=\left(y-2009\right)\left(2x+5y\right)\)
4, \(35x\left(y-8\right)-14y\left(8-y\right)=\left(y-8\right)\left(35x+14y\right)=7\left(5x+2y\right)\left(y-8\right)\)
5, \(x^2+14x+49=x^2+2.7x+7^2=\left(x+7\right)^2\)
6, \(9x^2-4=\left(3x-2\right)\left(3x+2\right)\)
Trả lời:
1, 15x2 + 10xy = 5x ( 3x + 2y )
2, 24x - 18y + 30 = 6 ( 4x - 3y + 5 )
3, 2x ( y - 2009 ) + 5y ( y - 2009 ) = ( y - 2009 )( 2x + 5y )
4, 35x ( y - 8 ) - 14y ( 8 - y ) = 35x ( y - 8 ) + 14y ( y - 8 ) = ( y - 8 )( 35x + 14y ) = 7 ( y - 8 )( 5x + 2y )
5, x2 + 14x + 49 = ( x + 7 )2
6, 9x2 - 4 = ( 3x - 2 )( 3x + 2 )