em ko biết làm

a. Giả sử: \(3+\sqrt{12}>\sqrt{16}\)

<=> \(\sqrt{12}>1\) (thỏa mãn)

Vậy \(3+\sqrt{12}>\sqrt{16}\)

b. \(4\sqrt{7}=\sqrt{4^2.7}=\sqrt{112}\)

\(3\sqrt{13}=\sqrt{3^2.13}=\sqrt{117}\)

Ta thấy: 112 < 117

Vậy \(4\sqrt{7}< 3\sqrt{13}\)

1. comfortable 

3. unhealthy

4. illness

  My hobby is listening to music. I started this hobby 2 years ago, when I saw an interesting music show on TV and I liked it right away. After that, I shared my hobby with my brother, Phuc, and he liked it too. To continue my hobby, I always go to the concert, or listen to music in my free time. When I listen to music, I feel comfortable. Listening to music is very useful and helpful, so I will continue this hobby in the future.

 \(a)P=\left(\dfrac{x^2+2}{x^3-1}+\dfrac{x+1}{x^2+x+1}+\dfrac{1}{1-x}\right).\left(\dfrac{x^2}{x+1}+1\right).\left(x\ne1;x\ne-1\right).\\ P=\dfrac{x^2+2+x^2-1-x^2-x-1}{\left(x-1\right)\left(x^2+x+1\right)}.\dfrac{x^2+x+1}{x+1}.\\ P=\dfrac{x^2-x}{x-1}.\dfrac{1}{x+1}.\\ P=\dfrac{x\left(x-1\right)}{x-1}.\dfrac{1}{x+1}.\\ P=x.\dfrac{1}{x+1}.\\ P=\dfrac{x}{x+1}.\)

\(P=\dfrac{1}{4}.\Rightarrow\dfrac{x}{x+1}=\dfrac{1}{4}.\\ \Leftrightarrow4x-x-1=0.\\ \Leftrightarrow3x-1=0.\\ \Leftrightarrow x=\dfrac{1}{3}\left(TM\right).\)

MN là đường trung bình đúng không hay chỉ đơn thuần là song song thôi

35 x 3/4 +45,5 x 75/100 + 20,5 x75% - 0,75 

= 35. 0,75 + 45,5 . 0,75+ 20,5 . 0,75 - 0,75.1

= 0,75( 35+45,5 + 20,5 -1)

= 0,75.100

= 75

\(\left(2013.2014+2014.2015+2015.2016\right).\left(1+\frac{1}{3}-1-\frac{1}{3}\right)\)

\(=\left(2013.2014+2014.2015+2015.2016\right).0\)

= 0