Xét ΔBAD và ΔBED có

BA=BE

\(\widehat{ABD}=\widehat{EBD}\)

BD chung

Do đó: ΔBAD=ΔBED

=>\(\widehat{BAD}=\widehat{BED}\)

=>\(\widehat{BED}=90^0\)

Ta có: ΔBAD=ΔBED

=>DA=DE

Xét ΔDAM vuông tại A và ΔDEC vuông tại E có

DA=DE

\(\widehat{ADM}=\widehat{EDC}\)(hai góc đối đỉnh)

Do đó: ΔDAM=ΔDEC

=>\(\widehat{DMA}=\widehat{DCE}\)

eh

ehhhhhhhhhhhhhhhhhhh

Lâu vậy -_-

.c

                     Giải:

         \(\dfrac{9}{A}\) = \(\dfrac{B}{8}\) = \(\dfrac{15}{20}\) = \(\dfrac{C}{24}\)

          \(\dfrac{9}{A}\) = \(\dfrac{15}{20}\) = \(\dfrac{3}{4}\)

           A = 9 : \(\dfrac{3}{4}\) = 9 x \(\dfrac{4}{3}\) = 12

          \(\dfrac{B}{8}\) = \(\dfrac{15}{20}\) = \(\dfrac{3}{4}\)

          B = \(\dfrac{3}{4}\) x 8 = 6

          \(\dfrac{C}{24}\)  = \(\dfrac{15}{20}\) = \(\dfrac{3}{4}\)

          C = \(\dfrac{3}{4}\) x 24 = 18

Vậy A + B - C = 12 + 6 - 18 = 0

Chọn b.0

Chọn B nha

bae bake beck kip a piupo the péno

Baking also helps me to relax after a busy week with lots of homework 

1 While I was riding home, I saw an accident

2 When he was young, he used to smoke a lot

3 While Jane was taking a bath, the phone rang three times

4 While I was having lunch, James arrived

5 While we were having dinner, the lights went out

6 When I heard the doorbell, I went to the door

7 While we were standing outside the cinema, someone picked my pocket

8 While I was having breakfast, the telephone rang

9 While they were cooking, somebody broke into their house

10 While I was learning my old lessons, my sister was watching TV

1 While I was riding home, I saw an accident

2 When he was young, he smoked a lot

3 While Jane was taking a bath, the phone rang three times

4 While I was having lunch, James arrived

5 While we were having dinner, the light went out

B. Reading

1 Students often play soccer, table tennis or badminton

2 They sometimes go swimming in the swimming pools

3 They often practice playing musical instruments in the school music room

4 They usually rehearse plays

5 They often get together and talk about their stamps

Giúp em ạ