x y A B C M D E

Giải :a) Ta có BD // Ay (gt)

=> góc DBM = góc A (so le trong)

mà góc A = 90⁰ => góc BDM = 90⁰

Xét tam giác AMC và tam giác BMD

có góc A = góc DBM = 90⁰ (cmt)

   MA = MB(gt)

  góc AMC = góc BMD ( đối đỉnh)

=> tam giác AMC = tam giác BMD (g.c.g)

b) Ta có : tam giác AMC = tam giác BMD (cm câu a)

=> MC = MD ( hai cạnh tương ứng)

Xét tam giác MEC và tam giác MED

có MC = MD (cmt)

   CME = DME (gt)

 ME : chung

=> tam giác MEC = tam giác MED (c.g.c)

=> góc CEM = góc DEM (hai góc tương ứng) 

Mà tia EM nằm giữa ED và EC

=> EM là tia p/giác của góc DEC (Đpcm)

c) Ta có : tam giác AMC = tam giác BMD (cm câu a)

=> BD = AC ( hai cạnh tương ứng)

Mà DE = BD + BE

hay AC + BE = DE 

=> BE = DE - AC (1)

Ta lại có tam giác MEC = tam giác MED (cm câu b)

=> EC = ED (hai cạnh tương ứng) (2)

Từ (1) và (2) suy ra BE = CE - AC (Đpcm)

Có bạn nào không? Giúp mình với

1: She will have Peter wash her car tomorrow.

=> She will have her car washed by Peter tomorrow.

2:John gets his sister to clean his shirt

=> John gets his shirt cleaned by his sister.

3:I will get the dressmaker to make a new dress

=> I will get a new dress made by the dressmaker.

4: Anne had a friend type her composition

=> Anne had her composition typed by a friend.

5: He had a mechanic repair his car

=> He had his car repaired by a mechanic.

6: They had the police arrest the shoplifter

=> They had the shoplifter arrested.

7: He always lets his son play the guitar in his free time

=>His son is always let to play the guitar in his free time.

=>He always lets the guitar played by his son in his free time.

8:Nobody makes friends with him

=>He isn't made friends with.

9:Her mother made him tidy his room yesterday

=>His mother made his room tidied yesterday.

=>Her mother made his room

10:People believe that we are working very well 

=>It is believed that we are working very well.

=>We are believed to be working very well.

thanks

đáp án 4 ảnh

\(\text{Ta có :}2^{91}=(2^{13})^7=8192^7\)

\(5^{35}=(5^5)^7=3125^7\)

Mà 8192 > 3125 nên 8192⁷ > 3125⁷ hoặc 2⁹¹ > 5³⁵

Vậy : 2⁹¹ > 5³⁵

TA có :

2⁹¹ = ( 2¹³ )⁷ = 8192⁷ ( 1 )

5³⁵ = ( 5⁵ )⁷ = 3125⁷ ( 2 )

Từ ( 1 ) và ( 2 ) => 2⁹¹ > 5³⁵

\(25.\left(-\frac{1}{5}\right)^3+\frac{1}{5}-2.\left(-\frac{1}{2}\right)^2-\frac{1}{3}\)

\(\Leftrightarrow25.\left(-\frac{1}{5}\right)^3-2.\left(-\frac{1}{2}\right)^2+\frac{1}{5}-\frac{1}{2}\)

\(\Leftrightarrow-\frac{1}{5}-2.\left(-\frac{1}{2}\right)^2+\frac{1}{5}-\frac{1}{2}\)

\(\Leftrightarrow-\frac{1}{5}+\frac{1}{5}-2\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)

\(\Leftrightarrow-2.\left(-\frac{1}{2}\right)^2-\frac{1}{2}\)

\(\Leftrightarrow-\frac{1}{2}-\frac{1}{2}\)

\(\Leftrightarrow\frac{-1-1}{2}\)

\(\Rightarrow-1\)