Thu gọn: (x-9)^2-(x+3)^2 (x+1)^2+(x-3)^2-2.(x+1).(x-3) (x-2)^2-(x-2).(x+3) 4x.(x-3)-3x.(2+x) 2x.(5x+2)+(2x-3).(3x-1) (x-1)^2-

2 bình luận về “Thu gọn: (x-9)^2-(x+3)^2 (x+1)^2+(x-3)^2-2.(x+1).(x-3) (x-2)^2-(x-2).(x+3) 4x.(x-3)-3x.(2+x) 2x.(5x+2)+(2x-3).(3x-1) (x-1)^2-”

1. Gửi bạn!

    

   

   Trả lời
2. Giải đáp:

    (x-9)^{2}-(x+3)^{2}

   =[(x-9)-(x+3)].[(x-9)+(x+3)]

   =(x-9-x-3).(x-9+x+3)

   =(-12).(2x-6)

   =-24x+72

   ________________

   (x+1)^{2}+(x-3)^{2}-2.(x+1).(x-3)

   =(x+1)^{2}-2.(x+1).(x-3)+(x-3)^{2}

   =[(x+1)-(x-3)]^{2}

   =(x+1-x+3)^{2}

   =4^{2}

   =16

   __________________

   (x-2)^{2}-(x-2).(x+3)

   =x^{2}-4x+4-(x^{2}+3x-2x-6)

   =x^{2}-4x+4-x^{2}-x+6

   =(x^{2}-x^{2})-(4x+x)+(4+6)

   =-5x+10

   ________________

   4x.(x-3)-3x.(2+x)

   =4x^{2}-12x-6x-3x^{2}

   =(4x^{2}-3x^{2})-(12x+6x)

   =x^{2}-18x

   ________________

   2x.(5x+2)+(2x-3).(3x-1)

   =10x^{2}+4x+(6x^{2}-2x-9x+3)

   =10x^{2}+4x+6x^{2}-11x+3

   =16x^{2}-7x+3

   _________________

   (x-1)^{2}-(x+2).(x-2)

   =x^{2}-2x+1-(x^{2}-4)

   =x^{2}-2x+1-x^{2}+4

   =-2x+5

   ________________

   (1+2x)^{2}+2.(1+2x).(x-1)+(x-1)^{2}

   =[(1+2x)+(x-1)]^{2}

   =(1+2x+x-1)^{2}

   =(3x)^{2}

   =9x^{2}

   #DYNA

    

   Trả lời