1+2+3+4+..+x=55

[(x+1).x]:2=55

(x+1).x=110

(x+1).x=11.10

=> x+1=11 hoặc x=10

=> x=10.        ,    x=10

vậy x=10

tìm và sửa lỗi sai:

What do you do if you lost your passports?
-> will

sitting around a burning campfire is a fun way to relax...for...a day of hiking.unluckily,many campers .......don't.....know how to...keep..their fires safe .forests are easy to catch fire but it is extremely difficult to stop a forest fire.each day,forest fires burn.......plants..........,kill animal.It is .........reason........that when you have a fire,you should make it a safe fire

Hai câu này thì mk biết

1a.engineer b.national c.scientist d. figure

2a,intelligent b,interest c.dependent d.computer

\(\Leftrightarrow28\left(5a+7b\right)=29\left(6a+5b\right)\Leftrightarrow140a+196b=174a+145b\Leftrightarrow51b=34a\Leftrightarrow\frac{a}{b}=\frac{51}{34}=\frac{3}{2}\)

Vì (a;b) =1

=> a =3 ; b =2

what is an amazing building
How amazing an bulding is!

what is an amazing building

how amazing building is !

choose the best answer

1.I don't like stories__which____ have unhappy endings

What is Mai's weight?

How heavy is Mai?

1) You should wash your hands before meals

-> You ought to wash your hands before meals.

2) What is your weight?

-> How heavy are you?