b/ áp dụng CM=C%x10D/Mct

CM=92x10x0.8/50=14.72M

a/ 50cm3=50ml=0.05l

nNH3=336/22.4=15(mol)

Cm = 15/0.05=300(M)

x = (3-4\(\sqrt{2}\))/3\(\sqrt{2}\)

đề thiếu 

Why do you come home late? 

-> What_____________________

It is common knowledge that he has been in prison several times.

->He is known_______________________________

She cannot get into the habit of studying every evening.

She cannot be __________________________________________

từ a^3 + b^3 + c^3 =3abc => a+b+c = 0 

=> a+b= -c  <=> c^2 = (a+b)^2 

tương tự với -b và -a 

=> P = ab^2/a^2+b^2-a^2-2ab-b^2 + bc^2/b^2+c^2-b^2-2bc-c^2 + ca^2/c^2 + a^2 - c^2-2ac-a^2

= -a/2 - b/2 - c/2 = -1/2(a+b+c)=0

đường kính TĐ = 142796/10 = 14279,6 ( km )

khối lượng TĐ = 1,9x10^27/318 = 597 x 10^22

tương tự nhé 

ab² hay là a²b²