1690

thank

mất cả 4 acc r, chán

REFER

Today is Tuesday, and it is also a special day for me. This morning I started everything with a delicious breakfast from my mother. She cooked me noodle with pork, egg, and vegetables. I went to school with my best friend Trinh, and we just had enough time to talk about our favorite TV show last night. I had a Math test today, so I was a little bit worried when the class started. It turned out that I was able to do well on the test, and I felt so proud about myself for the rest of the day. In the afternoon, I came to Trinh’s house to have lunch with her because her parents rarely came home in the middle of the day. We made a perfect meal from the ingredients that her mother had bought in the morning. We took a quick nap before having some other classes at school. We had a Physical Education class; today we learn how to have a badminton match. Trinh and I were a team; and although our team failed totally, we had a great time playing outside with other friends. I thought everything was just being ordinary as usual, but I had no idea there was a big surprise that was waiting for me at home. When I first stepped into my house, I saw the entire family gathering around a box in the corner. It turned out that my father had brought home a puppy, and it was the most beautiful creature to me. After finished all of my homework, I ended the day with a cup of hot milk. Now the puppy is sleeping right next to me, and I have to turn off the light so she can sleep peacefully. Today is such a happy day

\(x-\sqrt{2x-5}=4\)

ĐK: \(\left\{{}\begin{matrix}2x-5\ge0\\x\ge4\end{matrix}\right.\)\(\Leftrightarrow x\ge4\)

\(x-\sqrt{2x-5}=4\Leftrightarrow\sqrt{2x-5}=x-4\)

Ta bình phương 2 vế:

\(2x-5=\left(x-4\right)^2\)

\(\Leftrightarrow2x-5=x^2-8x+16\)

\(\Leftrightarrow x^2-10x+21=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x=7\left(nhận\right)\\x=3\left(loại\right)\end{matrix}\right.\)

C

B

a 3.76 + 15 = 18.76

b 67 - 2.59 = 64.41

c 8.25 x 0.76 = 6.27

d 20 : 2.5 = 20 x 0.4 = 8

e 8.6 : 0.5 = 8.6 x 2 = 17.2

Ta thấy số nào tận cùng là 5 nhân với bao nhiêu vẫn bằng 5.

Mà 11 x 13 x 15 tận cùng là 5 => Cả dãy tận cùng là 5