`c,(-x^2 +1)(-x+3)-x^2 (x-3)=10`

`<=>x^3 -x -3x^2 +3 -x^3 +3x^2 -10=0`

`<=>(x^3 -x^3)-(3x^2 -3x^2) -x+(3-10)=0`

`<=>-x-7=0`

`<=>-x=7`

`<=>x=-7`

Vậy `x=-7`

`d,(2x+3)(-x-1)-2x(-x-3)=12`

`<=>-2x^2 -3x-2x-3+2x^2 +6x-12=0`

`<=>(-2x^2 +2x^2)+(6x-2x-3x)-(3+12)=0`

`<=>x-15=0`

`<=>x=15`

Vậy `x=15`

`21036-17202:94+7458`

`=21036-183+7458`

`=20853+7458`

`=28311`

`c,(-x^2 +1)(-x+3)-x^2 (x-3)=10`

`<=>x^3 -x -3x^2 +3 -x^3 +3x^2 -10=0`

`<=>(x^3 -x^3)-(3x^2 -3x^2) -x+(3-10)=0`

`<=>-x-7=0`

`<=>-x=7`

`<=>x=-7`

Vậy `x=-7`

`d,(2x+3)(-x-1)-2x(-x-3)=12`

`<=>-2x^2 -3x-2x-3+2x^2 +6x-12=0`

`<=>(-2x^2 +2x^2)+(6x-2x-3x)-(3+12)=0`

`<=>x-15=0`

`<=>x=15`

Vậy `x=15`

Ta có sơ đo:

Kho `1``:` |--|--|      }

                               } `235` tấn

Kho `2``:` |--|--|--|   }

Số tấn thóc ở  kho `1` là:

`235:(2+3)xx2=94(tấn)`

Số tấn thóc ở  kho `2` là:

`234-94=141(tấn)`

Đổi: `94` tấn `=` `94000 kg`

        `141` tấn `=` `141000 kg`

      Đáp số: Kho `1``:` `94000 kg`

                    Kho `2``:` `141000 kg`

`a,25xx9xx4`

`=(25xx4)xx9`

`=100xx9`

`=900`

`b,36xx125xx8`

`=36xx(125xx8)`

`=36xx1000`

`=36000`

`c,34xx5xx2`

`=34xx(5xx2)`

`=34xx10`

`=340`

`d,135xx6xx2`

`=(135xx2)xx6`

`=270xx6`

`=1620`

\(\left(a+b\right)\left(a+b\right)\left(a+b\right)\\ =\left[a\left(a+b\right)+b\left(a+b\right)\right]\left(a+b\right)\\ =\left(a^2+ab+ab+b^2\right)\left(a+b\right)\\ =\left(a^2+2ab+b^2\right)\left(a+b\right)\\ =a^2\left(a+b\right)+2ab\left(a+b\right)+b^2\left(a+b\right)\\ =a^3+a^2b+2a^2b+2ab^2+ab^2+b^3\\ =a^3+3a^2b+3ab^2+b^3\)

`3/5 : 1/6 + 3:5 + 6/10 xx12 + 12/20`

`=3/5 xx 6 + 3/5 + 3/5 xx12 + 3/5`

`=3/5 xx (6+1+12+1)`

`=3/5 xx20`

`=12`