Ai giúp mk với
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360. Scientists ( để -s vì có have ) have researched science subjects.
361. His father is an architect.
362. Japan is an idustrial.
363. The solution of the book..
364. Every success...
365. Can you imagine .... ( Câu này chưa chắc )
366. The United Nations organization...
Giải:
3/2016+3/2017-3/2018 / 5/2018-5/2017-5/2016
=3.(1/2016+1/2017-1/2018)/5.(1/2018-1/2017-1/2016)
=-3/5
Chúc bạn học tốt!
Bài 1:
a: x=4
nên x+1=5
\(A=x^5-x^4\left(x+1\right)+x^3\left(x+1\right)-x^2\left(x+1\right)+x\left(x+1\right)-1\)
\(=x^5-x^5-x^4+x^4+x^3-x^3-x^2+x^2+x-1\)
=x-1
=4-1
=3
First, I am going to visit Ha Long Bay for two days
Then, I am going to see Ngoc Son Temple in Ha Noi for a week
Next, I am going to visit Hue for a week.
After that, I am going to see the citadel
Next, I am going to stay at a friend's house in Nha Trang for three days
Then, I am going to stay with their uncle in Ho Chi Minh City for a week
After that, I am going to visit the beach and swim in Nha Trang
Next, I am going to visit my friend
Then, I am going to see a movie
After that, I am going to wath a soccer match
2x−92402x−9240=39803980⇒⇒2x−92x−9=240.3980240.3980=117117
2x−9=1172x−9=117⇒⇒2x=117+9=1262x=117+9=126⇒⇒x=126:2=63
Ta có: -3x-10=-2x-5
\(\Leftrightarrow-3x-10+2x+5=0\)
\(\Leftrightarrow-x-5=0\)
\(\Leftrightarrow-x=5\)
hay x=-5
Vậy: x=-5
Lời giải:
Đặt $\frac{a}{c}=\frac{c}{b}=k\Rightarrow a=ck; c=bk$.
Khi đó:
a.
$\frac{a^2+c^2}{b^2+c^2}=\frac{(ck)^2+c^2}{b^2+(bk)^2}=\frac{c^2(k^2+1)}{b^2(k^2+1)}=\frac{c^2}{b^2}=\frac{(bk)^2}{b^2}=k^2(1)$
$\frac{a}{b}=\frac{ck}{b}=\frac{bk.k}{b}=k^2(2)$
Từ $(1); (2)\Rightarrow \frac{a^2+c^2}{b^2+c^2}=\frac{a}{b}$
b.
$\frac{b^2-a^2}{a^2+c^2}=\frac{b^2-(ck)^2}{(ck)^2+c^2}$
$=\frac{b^2-c^2k^2}{c^2(k^2+1)}=\frac{b^2-b^2k^4}{c^2(k^2+1)}$
$=\frac{b^2(1-k^4)}{c^2(k^2+1)}=\frac{b^2(1-k^2)(1+k^2)}{c^2(k^2+1)}$
$=\frac{b^2(1-k^2)}{c^2}=\frac{b^2(1-k^2)}{b^2k^2}=\frac{1-k^2}{k^2}(3)$
Và:
$\frac{b-a}{a}=\frac{b-ck}{ck}=\frac{b-bk^2}{bk^2}=\frac{b(1-k^2)}{bk^2}=\frac{1-k^2}{k^2}(4)$
Từ $(3); (4)$ suy ra $\frac{b^2-a^2}{a^2+c^2}=\frac{b-a}{a}$
cảm ơn ạ