\(=\left(5x^2+10xy\right)-\left(4x+8y\right)\)

\(=5x\left(x+2y\right)-4\left(x+2y\right)\)

\(=\left(x+2y\right)\left(5x-4\right)\)

5x² + 10xy - 4x - 8y

= ( 5x² +10xy )-( 4x+8y )

= 5x( x + 2y) - 4( x+2y)

=(x+2y)(5x-4)

Chọn câu C

`(4\sqrt{6}+x)^2=8^2+(6+\sqrt{x^2+4})^2`

`<=>96+8\sqrt{6}x+x^2=64+36+12\sqrt{x^2+4}+x^2+4`

`<=>2\sqrt{6}x-2=3\sqrt{x^2+4}`    `ĐK: x >= \sqrt{6}/6`

`<=>24x^2-8\sqrt{6}x+4=9x^2+36`

`<=>15x^2-8\sqrt{6}x-32=0`

`<=>x^2-[8\sqrt{6}]/15x-32/15=0`

`<=>(x-[4\sqrt{6}]/15)^2-64/25=0`

`<=>|x-[4\sqrt{6}]/15|=8/5`

`<=>[(x=[24+4\sqrt{6}]/15 (t//m)),(x=[-24+4\sqrt{6}]/15(ko t//m)):}`

2x ( x - y ) - 10y ( x - y )

= ( x - y ) ( 2x - 10y )

= ( x - y ) ( 2 . x - 2 . 5y )

= ( x - y ) ( x - 5y ) 2

2x ( x - y ) - 10y ( x - y )

= ( x - y ) ( 2x - 10y )

= ( x - y ) ( 2 . x - 2 . 5y )

= ( x - y ) ( x - 5y ) 2

a) 66,8 : 89 = 0,7505...

b) 8,568 : 3,6 = 2,38

c) 429 : 572 = 0,75

d) 127 : 25,4 = 0,005

Chúc bạn học tốt.

😁😁😁

\(5\sqrt{\dfrac{1}{2}}+\dfrac{1}{2}\sqrt{20}+\sqrt{5}\)

\(=\dfrac{5\sqrt{2}}{2}+\sqrt{5}+\sqrt{5}=\dfrac{5\sqrt{2}}{2}+2\sqrt{5}\)

\(=\dfrac{5\sqrt{2}}{2}+\dfrac{4\sqrt{5}}{2}=\dfrac{5\sqrt{2}+4\sqrt{5}}{2}\)

\(5\sqrt{\dfrac{1}{2}}+\dfrac{1}{2}\sqrt{20}+\sqrt{5}=\dfrac{5}{\sqrt{2}}+\dfrac{\sqrt{20}}{2}+\sqrt{5}=\dfrac{5\sqrt{2}+\sqrt{20}}{2}+\sqrt{5}=\dfrac{\sqrt{50}+\sqrt{20}}{\sqrt{4}}+\sqrt{5}=\dfrac{\sqrt{10}\left(\sqrt{5}+\sqrt{2}\right)}{\sqrt{4}}+\sqrt{5}=\dfrac{\sqrt{5}\left(\sqrt{5}+\sqrt{2}\right)}{\sqrt{2}}+\sqrt{5}=\dfrac{5+\sqrt{10}+\sqrt{10}}{\sqrt{2}}=\dfrac{5+2\sqrt{10}}{\sqrt{2}}\)

em ăn nhiều bánh nhất

em ăn \(\dfrac{1}{2}=\dfrac{3}{6}\) cái bánh

chị ăn \(\dfrac{2}{3}=\dfrac{4}{6}\) cái bánh

⇒chị ăn nhiều bánh hơn

(cách mình trình bày chắc chắn là không đúng nên bạn trình bày lại theo cách cô chỉ nha!)