-no face no name no number; forever; say you will

- lemon tree, attention; why not me

- until you; big big world ; just give me a reason

- yesterday once more; she ; rhythm in the rain

- season in the son; as long as you love me; baby ( justin bieber)

- let her go; everytime we touch ; safe and sound

- I do (911) ; take me to your heart; what are world

- Love story; shake it off ( taylor swift); one in a million

- All I have is love ; 7 years; nothing wanna my love for you

- Love me like you do; call me maybe; my love

..................................còn rất nhiều!

Ta có: \(\sqrt{x^2+x+2}=x^2-x+2\)

<=> \(x^2+x+2=\left(x^2-x+2\right)^2\)

<=> \(x^2+x+2=x^4+x^2+4-2x^3+4x^2-4x\)

<=> \(x^4-2x^3+4x^2-5x+2=0\)

<=> \(\left(x^4-x^3\right)-\left(x^3-x^2\right)+\left(3x^2-3x\right)-\left(2x-2\right)=0\)

<=> \(x^3\left(x-1\right)-x^2\left(x-1\right)+3x\left(x-1\right)-2\left(x-1\right)=0\)

<=> \(\left(x-1\right)\left(x^3-x^2+3x-2\right)=0\)

<=> \(x-1=0\) ( Vì \(x^3-x^2+3x-2\) vô nghiệm)

<=> \(x=1\)

7^14=(7²)⁷=49⁷

3^21=(3³)⁷=27⁷

Vì 49^7>27^7

Nên 7^14>3^21

PTHH: Al + 6HCl --> 2AlCl₃ + 3H₂ (1)

Fe + 2HCl --> FeCl₂ + H₂ (2)

Mg + 2HCl --> MgCl₂ + H₂ (3)

Ta có: n_H2 = \(\dfrac{11,2}{22,4}\) = 0,5 mol

Theo PT: n_HCl (1+2+3) = 2n_H2 (1+2+3)

=> n_HCl = 0,5.2 = 1 mol

Áp dụng ĐLBTKL ta có:

m_hh + m_HCl = m_{muối sau p/ứ} + m_H2

=> m_{muối sau p/ứ} = 13,4 + 1. 36,5 - 0,5.2 = 48,9g

=> Đáp án A

cx đc nhg so vs bn của tui thì ko ăn thua đâu! kakaka