:V

\(\left(-5\right)-25-\left(-34\right)-4\)

\(=-5-25+34-4\)

\(=\left(-5-25\right)+\left(34-4\right)\)

\(=-30+30\)

\(=0\)

\(#Wee\)

Tâm giải sai :

Ta có :

\(AB^2+BC^2=8^2+15^2\)

\(AB^2+BC^2=62+225=289\left(1\right)\)

mà \(AC^2=17^2=289\)

\(\rightarrow\) \(AB^2+BC^2=AC^2\)

\(\rightarrow\) \(\Delta ABC\) là tam giác vuông ( định lí \(Py-ta-go\)  )

\(#Wee\)

5 . 3² - 7

= 5 . 9 - 7

= 45 - 7

= 38

=> Chọn A

1. Do you often walk?

=> Yes,I do because it's good for my health

2. Did you walk much when you were a child?

=> Yes,I do

3. Do you think people walk more nowadays than they did in the past?

=> No because I see most people now they are always immersed in the virtual world or stay at home, lazy to exercise