(5-7x)(5+7x) (x+1)(x*2-x+1) (2x-3)(11-6x) (4x+3)(6-x) (9x-25)7

0 bình luận về “(5-7x)(5+7x) (x+1)(x*2-x+1) (2x-3)(11-6x) (4x+3)(6-x) (9x-25)7”

1. ?) `(5-7x)(5+7x)`

   `=5(5+7x)-7x(5+7x)`

   `=25+35x-35x+49x^2`

   `=25+49x^2`

   ?) `(x+1)(x^2-x+1)`

   `=x(x^2-x+1)+1(x^2-x+1)`

   $=xx^2-xx+x1+x^2-1x+1.1$

   `=x^3-x^2+1x+x^2-1x+1`

   `=x^3+(-x^2+x^2)+(1x-1x)+1`

   `=x^3+1`

   ?) `(2x-3)(11-6x)`

   `=2x(11-6x)-3(11-6x)`

   `=2×11-2x6x-3.11-3.6x`

   `=22x-12x^2-33-18x`

   `=(22x-18x)-12x^2-33`

   `=4x-12x^2-33`

   ?) `(4x+3)(6-x)(9x-25)7`

   `=4x(6-x)+3(6-x).7(9x-25)`

   `=24x-4x^2+18-3x.63x-175`

   `=24x-4x^2+18-189x^2-175`

   `=24x+(-4x^2-189x^2)+(18-175)`

   `=24x-193x^2-157`

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