ai giúp mik vs mik cần gấp
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Câu 3:
a: Áp dụng tính chất của dãy tỉ số bằng nhau, ta được:
\(\dfrac{x}{3}=\dfrac{y}{2}=\dfrac{x+y}{3+2}=\dfrac{90}{5}=18\)
Do đó: x=54; y=36
1,\(\sqrt{\left(x-1\right)^2}=\left|x-1\right|=-\left(x-1\right)=1-x\)
2,\(\sqrt{\left(a-2b\right)^2}=\left|a-2b\right|=-\left(a-2b\right)=2b-a\)
3,\(\sqrt{\left(2x-1\right)^2}=\left|2x-1\right|=2x-1\)
Bài 5:
Gọi số sách 7A,7B,7C,7D lần lượt là \(a,b,c,d\in \mathbb{N^*},sách\)
Áp dụng tc dtsbn:
\(\dfrac{a}{37}=\dfrac{b}{37}=\dfrac{c}{40}=\dfrac{d}{36}=\dfrac{c-d}{40-36}=\dfrac{12}{4}=3\\ \Rightarrow\left\{{}\begin{matrix}a=111\\b=111\\c=120\\d=108\end{matrix}\right.\)
Vậy ...
Bài 6:
Gọi cd, cr theo thứ tự là \(a,b>0;m\)
\(\Rightarrow a:b=5:4\Rightarrow\dfrac{a}{5}=\dfrac{b}{4}\)
Đặt \(\dfrac{a}{5}=\dfrac{b}{4}=k\Rightarrow a=5k;b=4k\)
Mà \(ab=500\Rightarrow20k^2=500\Rightarrow k^2=25\Rightarrow k=5\left(k>0\right)\)
\(\Rightarrow\left\{{}\begin{matrix}a=5\cdot5=25\\b=5\cdot4=20\end{matrix}\right.\\ \Rightarrow\text{Chu vi là }2\left(a+b\right)=2\left(25+20\right)=90\left(m\right)\)
25. amusement.
26. relaxed.
27. diving.
28. operate
29. environmentally
30. largest.
- Bạn tham khảo đáp án nhé! Chúc bạn học tốt.
1. D => bỏ
2. C
3. C
4. A => the
5. A
6. C => next
7. C => taught
8. C => the most
9. D => from
10. B => would
II
1. I wish I would become a singer.
2. She used to walk to school when she was a child.
3. If I were you, I would learn Chinese
4. The man who I met yesterday was my uncle
5. The trees are watered by me everyday
Bài 1:
a: 4/9=4/9
5/3=15/9
b: 3/14=-18/84
-5/6=-70/84
c: -2/25=-14/175
-3/35=-15/175
d: -7/20=-35/100
-11/25=-44/100
e: -25/75=-1/3=-5/15
-12/30=-2/5=-6/15
-12 . x - 7 . x = -76
Mẫu: x = 1 => -19
x Kết quả
1 -19
2 -38
3 -57
4 -76
thì kết quả chính xác là x = 4
\(a,\dfrac{11x}{2x-5}+\dfrac{x-30}{2x-5}=\dfrac{11x+x-30}{2x-5}=\dfrac{12x-30}{2x-5}=\dfrac{6\left(2x-5\right)}{2x-5}=6\)
\(b,\dfrac{3x^2-1}{2x}+\dfrac{x^2+1}{2x}=\dfrac{3x^2-1+x^2+1}{2x}=\dfrac{4x^2}{2x}=2x\)
\(c,\dfrac{3}{2x-5}+\dfrac{-2}{2x+5}+\dfrac{-20}{4x^2-25}=\dfrac{3\left(2x+5\right)}{\left(2x-5\right)\left(2x+5\right)}-\dfrac{2\left(2x-5\right)}{\left(2x-5\right)\left(2x+5\right)}-\dfrac{20}{\left(2x-5\right)\left(2x+5\right)}=\dfrac{6x+15-4x+10-20}{\left(2x-5\right)\left(2x+5\right)}=\dfrac{2x+5}{\left(2x-5\right)\left(2x+5\right)}=\dfrac{1}{2x-5}\)
\(d,\dfrac{x-2}{x-1}+\dfrac{x-3}{x+1}+\dfrac{4-2x^2}{x^2-1}=\dfrac{\left(x-2\right)\left(x+1\right)+\left(x-3\right)\left(x-1\right)+4-2x^2}{\left(x-1\right)\left(x+1\right)}=\dfrac{x^2-2x+x-2+x^2-3x-x+3+4-2x^2}{\left(x-1\right)\left(x+1\right)}=\dfrac{-5x+5}{\left(x-1\right)\left(x+1\right)}=\dfrac{-5\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}=\dfrac{-5}{x-1}\)
\(e,\dfrac{x+1}{x-1}+\dfrac{1-x}{x+1}+\dfrac{4}{x^2-1}=\dfrac{\left(x+1\right)^2}{\left(x-1\right)\left(x+1\right)}-\dfrac{\left(x-1\right)^2}{\left(x-1\right)\left(x+1\right)}+\dfrac{4}{\left(x-1\right)\left(x+1\right)}=\dfrac{x^2+2x+1-x^2+2x-1+4}{\left(x-1\right)\left(x+1\right)}=\dfrac{4x+4}{\left(x-1\right)\left(x+1\right)}=\dfrac{4\left(x+1\right)}{\left(x-1\right)\left(x+1\right)}=\dfrac{4}{x-1}\)
1. Where is the teacher right now?
2. Where is Dr Green staying?
3. How do you get to your new office?
4. What do the contruction workers do in the park?
5. When does she leave for work?
6. Where did he go yesterday?
7. Who will she have dinner with tomorrow night?
8. Why will she sleep in her sofa?
9. Who are studying C in the laboratory?
10. How long does it take you to go to school?