chúc mừng mọi người nha :3 

ĐK: x ≥ -1

Bình phương 2 vế, ta đc:

\(x^2+3x+1=x+1\)

⇔ \(x^2+\text{2}x=0\)

⇔ \(x\left(x+2\right)=0\)

⇒ \(\left[{}\begin{matrix}x=0\\x+2=0\end{matrix}\right.\) ⇔ \(\left[{}\begin{matrix}x=0\left(TM\right)\\x=-2\left(KTM\right)\end{matrix}\right.\)

Vậy x = 0

Ta có: \(x=9-4\sqrt{5}\)

⇔ \(\sqrt{x}=\sqrt{9-4\sqrt{5}}=\sqrt{5-4\sqrt{5}+4}\)

⇔ \(\sqrt{x}=\sqrt{\left(\sqrt{5}-2\right)^2}=\left|\sqrt{5}-2\right|\)

⇔ \(\sqrt{x}=\sqrt{5}-2\)   

Khi đó:    \(P=\dfrac{1-\sqrt{5}+2}{\sqrt{5}-2+2}=\dfrac{3-\sqrt{5}}{\sqrt{5}}\)

⇔ A = \(3\sqrt{3}-4\sqrt{3}-5\sqrt{3}\)

⇔ \(A=-6\sqrt{3}\)

cái này lúc nãy e nhìn sai đề ạ 

1. A ball is round

2. The table has four legs

3. My dog has white fur

4. The cake has chocolate frosting

5. A year has twelve moths

6. I celebrate my birthday every year

1. A ball is round

2. The table has four legs

3. My dog has white fur

4. The cake has twelve months

5. I celebrate my birthday every year