In about 150 words, write about your Tet holiday

Turn these sentences into the passive voice

1. Let's tell them about it!

2. Don't let the other see you!

GT: hcn ABCD, \(AH\perp BD\)

      lấy \(E\in DH,K\in BC\) sao cho \(\dfrac{DE}{DH}=\dfrac{CK}{CB}\)

KL: a) \(\Delta ADE\sim\Delta ACK\)

      b) \(\Delta AEK\sim\Delta ADC\)

      c) \(\widehat{AEK}=90^0\)

\(\dfrac{5\left(1-2x\right)}{3}+\dfrac{x}{2}=\dfrac{3\left(x-5\right)}{4}\)

\(\Leftrightarrow\dfrac{20-40x}{12}+\dfrac{6x}{12}=\dfrac{9x-45}{12}\)

\(\Rightarrow20-40x+6x=9x-45\)

\(\Leftrightarrow6x-40x-9x=-45-20\)

\(-43x=-65\)

\(\Leftrightarrow x=\dfrac{65}{43}\)

1. Has the work been finished by Tom?

2. Were some exercises given by the teacher?

3. Have the window of the labratory been changed?

4. Is a poem going to be written ?

Bài 1: Đốt cháy toàn bộ 6,72 lít khí H₂ trong không khí

a) Viết PTHH

b)Tính khối lượng và thể tích của O₂

Bài 2: Tính số g nước thu được khi cho 8,4 lít H₂ tác dụng với 2,8 lít O₂ (cả 2 chất đều ở đktc)

a) \(9x^2-1=\left(3x-1\right)\left(5x+8\right)\)

\(\Leftrightarrow\left(3x-1\right)\left(3x+1\right)-\left(3x-1\right)\left(5x+8\right)=0\)

\(\Leftrightarrow\left(3x-1\right)\left(3x+1-5x-8\right)=0\)

\(\Leftrightarrow\left(3x-1\right)\left(-2x-7\right)=0\)

\(TH_1:3x-1=0\)

\(\Leftrightarrow x=\dfrac{1}{3}\)

\(TH_2:-2x-7=0\)

\(\Leftrightarrow x=-\dfrac{7}{2}\)

Vậy pt có tập nghiệm \(S=\left\{\dfrac{1}{3};-\dfrac{7}{2}\right\}\)

b) \(2x^3-5x^2+3x=0\)

\(\Leftrightarrow2x^3-2x^2-3x^2+3x=0\)

\(\Leftrightarrow2x^2\left(x-1\right)-3x\left(x-1\right)=0\)

\(\Leftrightarrow x\left(x-1\right)\left(2x-3\right)=0\)

\(TH_1:x=0\)

\(TH_2:x-1=0\)

\(\Leftrightarrow x=1\)

\(TH_3:2x-3=0\)

\(\Leftrightarrow x=\dfrac{3}{2}\)

Vậy pt có tập nghiệm \(S=\left\{0;1;\dfrac{3}{2}\right\}\)

c) \(9x^2-16-x\left(3x+4\right)=0\)

\(\Leftrightarrow\left(9x^2-16\right)-x\left(3x+4\right)=0\)

\(\Leftrightarrow\left(3x-4\right)\left(3x+4\right)-x\left(3x+4\right)=0\)

\(\Leftrightarrow\left(3x+4\right)\left(2x-4\right)=0\)

\(TH_1:3x+4=0\)

\(\Leftrightarrow x=-\dfrac{4}{3}\)

\(TH_2:2x-4=0\)

\(\Leftrightarrow x=2\)

Vậy pt có tập nghiệm \(S=\left\{-\dfrac{4}{3};2\right\}\)

d) \(\dfrac{5x+4}{3}-1=\dfrac{3x-2}{4}\)

\(\Leftrightarrow\dfrac{20x+16}{12}-\dfrac{12}{12}=\dfrac{9x-6}{12}\)

\(\Rightarrow20x+16-12=9x-6\)

\(\Leftrightarrow20x-9x=-6-16+12\)

\(\Leftrightarrow11x=-10\)

\(\Leftrightarrow x=-\dfrac{10}{11}\)

Vậy pt có nghiệm duy nhất \(x=-\dfrac{10}{11}\)