1. A → be

2. B → met

3. A → use

4. C → with

5. C → were

\(\dfrac{8}{x-5}=\dfrac{3}{x+1}\)

\(\Rightarrow8\left(x+1\right)=3\left(x-5\right)\)

\(\Rightarrow8x+8=3x-15\)

\(\Rightarrow5x=-23\)

\(\Rightarrow x=-\dfrac{23}{5}\) ( thỏa mãn đk )

Bài 1:

a. Hàm số \(y=\left(m^2-3m\right)x\) đồng biến 

\(\Leftrightarrow m^2-3m>0\Leftrightarrow m\left(m-3\right)>0\) \(\Leftrightarrow\left\{{}\begin{matrix}m>0\\m-3>0\end{matrix}\right.\) \(\Leftrightarrow m>3\)

Vậy m>3 thỏa mãn ycbt

b. Ta có hàm số đi qua \(A\left(1;-2\right)\) \(\Rightarrow-2=a.1\Rightarrow a=-2\)

Vậy hệ số góc của hàm số là a=-2

2-3+4 sao bằng 0 được 

a. \(3^3.2^2-4^2=9.4-4^2=4\left(9-4\right)=4.5=20\)

b. \(7^5:49-5^2=7^5:7^2-5^2=7^3-5^2=343-25=318\)

c. \(4.5^5:125=4.5^5:5^3=4.5^2=4.25=100\)

d. \(1024:\left(32.2^5\right)=2^{10}:\left(2^5.2^5\right)=2^{10}:2^{10}=1\)

e. \(\left(5^7+5^6+5^5\right):5^5=5^5\left(5^2+5+1\right):5^5=5^2+5+1=31\)

f. \(\left(5^{2019}-5^{2018}\right):5^{2018}=5^{2018}\left(5-1\right):5^{2018}=5-1=4\)

a. ĐKXĐ: \(x\ne\pm3\)

\(A=\dfrac{2x}{x+3}+\dfrac{x+1}{x-3}+\dfrac{3-11x}{9-x^2}\)

\(=\dfrac{2x}{x+3}+\dfrac{x+1}{x-3}-\dfrac{3-11x}{x^2-9}\)

\(=\dfrac{2x\left(x-3\right)+\left(x+1\right)\left(x+3\right)-\left(3-11x\right)}{x^2-9}\)

\(=\dfrac{2x^2-6x+x^2+4x+3-3+11x}{x^2-9}\)

\(=\dfrac{3x^2+9x}{x^2-9}=\dfrac{3x\left(x+3\right)}{\left(x+3\right)\left(x-3\right)}=\dfrac{3x}{x-3}\)

b. \(P=A.B\)

\(\Rightarrow P=\dfrac{3x}{x-3}.\dfrac{x-3}{x+1}=\dfrac{3x}{x+1}\) 

Ta có \(P=\dfrac{9}{2}\) 

\(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\\dfrac{3x}{x+1}=\dfrac{9}{2}\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\6x=9x+9\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\-3x=9\end{matrix}\right.\) \(\Leftrightarrow x=-3\)

c. \(B< 1\)

\(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\\dfrac{x-3}{x-1}< 1\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\\dfrac{x-3}{x-1}-1< 0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\\dfrac{2}{1-x}< 0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x\ne-1\\1-x< 0\end{matrix}\right.\) \(\Leftrightarrow x>1\)

Rewrite these following sentences, do not change meaning 

1. The children will decorate the house this weekend.

-> The house will be decorated by the children thí weekend

2. “How many students are there in your class?” Thanh said to me.

-> Thanh asked me how many students there were in my class

3. Work hard and you will get good grades.

-> If you work hard, you will get good grades

4. Linh doesn’t have a motorbike.

-> Linh wishes she had a motorbike 

5. He is a faster runner than I am.

-> He runs faster than I do

6. Despite her good performance, she didn’t received good comments from critics.

-> Although she performed well, she đin't received good comments from critics

belief

unknown/stolen

difficulty

population

flexible

Xét △ABK và △ACH có

∠AKB=∠AHC

∠A chung 

⇒ △ABK∼△ACH ( g_g )

⇒ ∠ABK=∠ACH ( hai góc tương ứng bằng nhau )