Toán Lớp 8: x²-25 8x++8y x²+2xy+y²-4 x³-2x²+x x²+4x-y²+4

Question

Toán Lớp 8:  x²-25 8x++8y x²+2xy+y²-4 x³-2x²+x x²+4x-y²+4

thanhthuythu · Answer

#Chery      a)  x^2 - 25     = x^2 - 5^2     = ( x - 5 )( x + 5 )    -->   &Aacute;p dụng :    a^2 - b^2 = ( a - b )( a + b )     b) 8x + 8y      = 8 ( x + y )     c) x^2 + 2xy + y^2 - 4     = ( x^2 + 2xy + y^2 ) - 2^2     = ( x + y )^2 - 2^2     = ( x + y - 2 )( x + y + 2 )    -->   &Aacute;p dụng :    a^2 - b^2 = ( a - b )( a + b )     d) x^3 - 2x^2 + x      = x ( x^2 - 2x + 1 )     = x ( x - 1 )^2    -->   &Aacute;p dụng :   ( a^2 - 2ab + b^2 ) = ( a - b )^2    e) x^2 + 4x - y^2 + 4      = ( x^2 + 4x + 4 ) - y^2     = ( x + 2 )^2 - y^2     = ( x + 2 - y )( x + 2 + y )    -->   &Aacute;p dụng :    a^2 - b^2 = ( a - b )( a + b )

cobebongdem · Answer

1)x^2-25   =x^2-5^2   =(x-5).(x+5)   2)8x+8y   =8.(x+y)   3)x^2+2xy+y^2-4   =(x^2+2xy+y^2)-2^2   =(x+y)^2-2^2   =(x+y-2).(x+y+2)   4)x^3-2x^2+x   =x.(x^2-2x+1)   =x.(x-2)^2   5)x^2+4x-y^2+4   =(x^2+4x+4)-y^2   =(x+2)^2-y^2   =(x+2-y).(x+2+y)   $#ch&uacute;c tus học tốt!!$   #La