Bài 1 : 1. $\sqrt{4+2}$$\sqrt{3}$ - $\sqrt{3}$ 2. $\sqrt{7-4}$$\sqrt{3}$ + $\sqrt{3}$ Bài 2 : 1. ($\sqrt{18}$ + $\sqrt{32}$ - $\sqrt{50}$) nhân $\sqrt{2}$ 2. $\sqrt{100}$ -$\sqrt{32}$ nhan $\sqrt{2}$ + $\sqrt{18}$ nhan $\sqrt{2}$ 3. ($\sqrt{12}$ + 3$\sqrt{75}$ - 4$\sqrt{27}$) nhan $\sqrt{3}$

Đáp án:

 Bài `1)`

`a)sqrt3.(sqrt6-1)`

`b)sqrt3.(sqrt3+1)`

Bài `2)`

`1)4`

`2)8`

`3)15`. 

Giải thích các bước giải:

 Bài `1)`

`1)sqrt(4+2).sqrt3-sqrt3`

`=sqrt3.(sqrt6-1)`

`2)sqrt(7-4).sqrt3+sqrt3`

`sqrt3.(sqrt3+1)`

Bài `2)`

`1)(sqrt(18)+sqrt(32)-sqrt(50)).sqrt2`

`=sqrt(18.2)+sqrt(32.2)-sqrt(50.2)`

`=sqrt(36)+sqrt(64)-sqrt(100)`

`=6+8-10`

`=4`

`2)sqrt(100)-sqrt(32).sqrt2+sqrt(18).sqrt2`

`=10-sqrt(64)+sqrt(36)`

`=10-8+6`

`=8`

`3)(sqrt(12)+3sqrt(75)-4sqrt(27)).sqrt3`

`=sqrt(12.3)+3sqrt(75.3)-4sqrt(27.3)`

`=sqrt(36)+3sqrt(225)-4sqrt(81)`

`=6+3.15-4.9`

`=6+45-36`

`=6+9`

`=15`. 

`@nguyen``nam500#hoidap247`. 

Bài 1:

Đáp án:

 a) $\sqrt{4+2}$ .$\sqrt{3}$ - $\sqrt{3}$

= $\sqrt{6}$ . $\sqrt{3}$ - $\sqrt{3}$

= $\sqrt{6.3}$ - $\sqrt{3}$

= $\sqrt{18}$ - $\sqrt{3}$

= $3\sqrt{2}$ - $\sqrt{3}$

b) $\sqrt{7-4}$ . $\sqrt{3}$ + $\sqrt{3}$

= $\sqrt{3}$ . $\sqrt{3}$ + $\sqrt{3}$

= 3 +$\sqrt{3}$

Bài 2:

Đáp án:

a) ( $\sqrt{9.2}$ + $\sqrt{16.2}$ - $\sqrt{25.2}$ )$\sqrt{2}$

= ( $3\sqrt{2}$ + $4\sqrt{2}$ - $5\sqrt{2}$ )$\sqrt{2}$

= 6 + 8 - 10

= 4

b) $\sqrt{100}$ - $\sqrt{32}$ . $\sqrt{2}$ + $\sqrt{18}$ . $\sqrt{2}$

= 10 - $\sqrt{64}$ + $\sqrt{36}$

= 10 - 8 + 6

= 8

c)( $\sqrt{12}$ +$3\sqrt{75}$ - $4\sqrt{27}$ )$\sqrt{3}$

= ( $\sqrt{4.2}$ + $4\sqrt{25.3}$ - $4\sqrt{9.3}$ )$\sqrt{3}$

= ($2\sqrt{3}$ + $15\sqrt{3}$ - $12\sqrt{3}$ )$\sqrt{3}$

= 6 + 45 - 36

= 15