ĐẶT x-1=a  , x+3=b   (a,b cùng dấu)

\(PT\Leftrightarrow ab+2a\sqrt{\frac{b}{a}}=8\)

\(\Leftrightarrow2a\sqrt{\frac{b}{a}}=8-ab\)

\(\Leftrightarrow4a^2\frac{b}{a}=64-16ab+a^2b^2\)

\(\Leftrightarrow a^2b^2-20ab+64=0\)

\(\Leftrightarrow\left(ab-10\right)^2-36=0\)

\(\Leftrightarrow\left(ab-4\right)\left(ab-16\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}ab=4\\ab=16\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\left(x-1\right)\left(x+3\right)=4\\\left(x-1\right)\left(x+3\right)=16\end{cases}}\)

Đến đây đơn giản rồi bn tự giải nhé

ĐK:....\(\frac{x+3}{x-1}\ge0\)

<=> \(\left(x-1\right)\left(x+3\right)+2\sqrt{\left(x-1\right)\left(x+3\right)}+1=9\)

<=> \(\left(\sqrt{\left(x-1\right)\left(x+3\right)}+1\right)^2=9\)

\(\Leftrightarrow\orbr{\begin{cases}\sqrt{\left(x-1\right)\left(x+3\right)}=2\\\sqrt{\left(x-1\right)\left(x+3\right)}=-4\left(loai\right)\end{cases}}\)

\(\Leftrightarrow\left(x-1\right)\left(x+3\right)=4\)

Em tự làm tiếp nhé

mình cảm ơn mn ak

\(5^{x+1}+5^{x+2}=750\)

\(\Leftrightarrow5^x.5^1+5^x.5^2=750\)

\(\Leftrightarrow5^x.5+5^x.25=750\)

\(\Leftrightarrow5^x.\left(5+25\right)=750\)

\(\Leftrightarrow5^x.30=750\)

\(\Leftrightarrow5^x=750:30\)

\(\Leftrightarrow5^x=25\)

\(\Leftrightarrow5^x=5^2\)

\(\Rightarrow x=2\)

5^{x + 1} + 5^{x + 2} = 750

=> 5^x . 5 + 5^x . 5² = 750

=> 5^x . (5 + 5²) = 750

=> 5^x . (5 + 25) = 750

=> 5^x . 30 = 750

=> 5^x = 750 : 30

=> 5^x = 25

=> 5^x = 5²

=> x = 2

Vậy x = 2

\(5^{x+1}+5^{x+2}=750.\)

\(5^x.5+5^x.5^2=750\)

\(5^x.\left(5+5^2\right)=750\)

\(5^x.\left(5+25\right)=750\)

\(5^x.30=750\)

\(5^x=750:30\)

\(5^x=25\)

\(\Rightarrow x=2\)

check ib mình vs ạ

is your father's age ?

I do not play the guitar as well as him

a, \(V_{CO}=\left(\dfrac{2,8}{28}\right).22,4=2,24l\\ V_{NO}=0,1.22,4=2,24l\\ V_{hh}=2,24+2,24=4,48l\)

b, \(V_{hh}=1,12+8,96=10,08l\)

lasts two months 

absent from school last Monday

prevented Mr Hoang from going to the party 

need to finish the work today

better not eat too much meat

more noise in the country than there is in the city

é tui thấy tờ giấy hình như you vẽ truyện đằng sau >:D

1 will have

2 looked

3 would understand

4 would arrive

5 swim

6 press

7 would call-were

8 listened

9 won't dry out

10 gave

11 won't find

12 would visit

1 will have

2 looked

3 would understand

4 would arrive

5 swim

6 press

7 would call-were

8 listened

9 won't dry out

10 gave

11 won't find

12 would visit

When was the black car sold 

The reported was finished by Nam this morning

The eletricty system is being checked by us now

1 D

2 B

3 D

4 B

5 A

1 D

2 B

3 D

4 B

5 A