Giúp em bài này với ạ. Em cảm ơn❤
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a) \(\dfrac{A}{x-3}=\dfrac{y-x}{3-x}\left(Đk:x\ne3\right)\)
\(A=\dfrac{\left(x-3\right)\left(y-x\right)}{3-x}=x-y\)
b) \(\dfrac{5x}{x+1}=\dfrac{Ax\left(x-1\right)}{\left(1-x\right)\left(x+1\right)}\left(Đk:x\ne\pm1\right)\)
\(A=\dfrac{5x\left(1-x\right)\left(x+1\right)}{x\left(x-1\right)\left(x+1\right)}=-5\)
c) \(\dfrac{4x^2-5x+1}{A}=\dfrac{4x-1}{x+3}\left(Đk:x\ne-3;A\ne0\right)\)
\(A=\dfrac{\left(4x^2-5x+1\right)\left(x+3\right)}{4x-1}=\dfrac{\left(x-1\right)\left(4x-1\right)\left(x+3\right)}{4x-1}\)
\(=\left(x-1\right)\left(x+3\right)=x^2+2x-3\)
1. What size shoes do you take?
2. What newspaper do you read?
3. What color are your eyes?
4. What time did you arrive this morning?
5. What kind of film do you like?
6. How tall is your teacher?
7. How far is it from your house to the office?
8. How much did you pay for your new shirt?
9. How often do you take an English test in class?
10. How long have you been studying English?
a/ Vì tb đang xếp thành 1 hàng => tb đang ở kì giữa NP hoặc GP2
Nếu ở Kì giữa NP => 2n = 24
Nếu ở KÌ giữa GP 2 => 2n = 48
b/ Vì các NST kép đang phân li về 2 cực => Tb đang ở kì sau GP1 => 2n = 32
câu 3.
Ta biết rằng khi chuyển đổi từ \(^oC->^oF\) ta có công thức
\(y=ax+b\)(trong đó x là số chỉ \(^oC\), y là chỉ \(^oF\))
theo bài ra=>hệ pt:\(\left\{{}\begin{matrix}32=a.0+b\\212=100a+b\end{matrix}\right.< =>\left\{{}\begin{matrix}b=32\\a=1,8\end{matrix}\right.\)
câu 4:
đường kính nón : \(35-10-10=15cm\)
=>bán kính nón: \(R=\dfrac{15}{2}=7,5cm^{ }\)
=>Sxq(nón)=\(\pi Rl=3,14.30.7,5\approx707cm^2\)
S(vành nón)=\(\pi\left(\dfrac{35}{2}\right)^2-\pi.\left(\dfrac{15}{2}\right)^2=785cm^2\)
S(vải cần thiết)=\(707+785=1492cm^2\)
do hao hụt 20% vải nên số vải cần để khâu mũ là:
\(1492+20\%.1492\approx1790cm^2\)
a) xét tg ABD và tg ACD có :
AB = AC (gt)
AD chung
Góc BAC = góc DAC( AD là p/g góc BAC)
=> tg ABD = tg ADC( c-g-c)
b)xét tg AMB và tg AMC có:
AM chung
AB = AC (gt)
góc BAM = góc CAM ( M thuộc AD)
=> tg ABM = tg ACM ( c-g-c)
c)vì tg ADB = tg ADC (cmt)
=> DB = DC (cạnh tương ứng )
Vì tg AMB = tg AMC (cmt)
=> BM = MC (cạnh tương ứng)
Xét tg MBD và tg MCD có
MB= MC (cmt)
MD chung
BD = DC ( cmt)
=> tg MBD = tg MCD ( c-c-c)
\(L=\lim\limits_{x\rightarrow+\infty}\left(2x^2-\sqrt{x^2-x}.\sqrt[3]{8x^3+12x^2-3x}\right)\)
Đặt \(f\left(x\right)=2x^2-\sqrt{x^2-x}.\sqrt[3]{8x^3+12x^2-3x}\)
Ta có:
\(2.f\left(x\right)=4x^2-\sqrt{4x^2-4x}.\sqrt[3]{8x^3+12x^2-3x}\)
\(=1+\left(4x^2-1\right)-\sqrt{4x^2-4x}.\sqrt[3]{8x^3+12x^2-3x}\)
\(=1+\left(2x-1\right)\left(2x+1-\sqrt[3]{8x^3+12x^2-3x}\right)+\left(2x-1-\sqrt{4x^2-4x}\right).\sqrt[3]{8x^3+12x^2-3x}\)
Đặt \(A\left(x\right)=\left(2x-1\right)\left(2x+1-\sqrt[3]{8x^3+12x^2-3x}\right)\)
\(B\left(x\right)=\left(2x-1-\sqrt{4x^2-4x}\right).\sqrt[3]{8x^3+12x^2-3x}\)
\(A\left(x\right)=\left(2x-1\right)\left(2x+1-\sqrt[3]{8x^3+12x^2-3x}\right)\)
\(=\dfrac{\left(2x-1\right)\left(8x^3+12x^2+6x+1-8x^3-12x^2+3x\right)}{\left(2x+1\right)^2+\sqrt[3]{\left(8x^3+12x^2-3x\right)^2}+\left(2x+1\right)\sqrt[3]{8x^3+12x^2-3x}}\)
\(=\dfrac{\left(2x-1\right)\left(9x+1\right)}{\left(2x+1\right)^2+\sqrt[3]{\left(8x^3+12x^2-3x\right)^2}+\left(2x+1\right)\sqrt[3]{8x^3+12x^2-3x}}\)
\(\Rightarrow\lim\limits_{x\rightarrow+\infty}A\left(x\right)=\lim\limits_{x\rightarrow+\infty}\dfrac{\left(2-\dfrac{1}{x}\right)\left(9+\dfrac{1}{x}\right)}{\left(2+\dfrac{1}{x}\right)^2+\sqrt[3]{\left(8+\dfrac{12}{x}-\dfrac{3}{x^2}\right)^2}+\left(2+\dfrac{1}{x}\right)\sqrt[3]{8+\dfrac{12}{x}-\dfrac{3}{x^2}}}\)
\(=\dfrac{2.9}{2^2+4+2.2}\)
\(=\dfrac{3}{2}\)
\(B\left(x\right)=\left(2x-1-\sqrt{4x^2-4x}\right).\sqrt[3]{8x^3+12x^2-3x}\)
\(=\dfrac{\left(4x^2-4x+1-4x^2+4x\right).\sqrt[3]{8x^3+12x^2-3x}}{2x-1+\sqrt{4x^2-4x}}\)
\(=\dfrac{\sqrt[3]{8x^3+12x^2-3x}}{2x-1+\sqrt{4x^2-4x}}\)
\(\Rightarrow\lim\limits_{x\rightarrow+\infty}B\left(x\right)=\lim\limits_{x\rightarrow+\infty}\dfrac{\sqrt[3]{8+\dfrac{12}{x}-\dfrac{3}{x^2}}}{2-\dfrac{1}{x}+\sqrt{4-\dfrac{4}{x}}}\)
\(=\dfrac{2}{2+2}\)
\(=\dfrac{1}{2}\)
\(\Rightarrow2L=\lim\limits_{x\rightarrow+\infty}\left[2f\left(x\right)\right]\)
\(=\lim\limits_{x\rightarrow+\infty}\left[1+A\left(x\right)+B\left(x\right)\right]\)
\(=1+\lim\limits_{x\rightarrow+\infty}A\left(x\right)+\lim\limits_{x\rightarrow+\infty}B\left(x\right)\)
\(=1+\dfrac{3}{2}+\dfrac{1}{2}\)
\(=3\)
\(\Rightarrow L=\dfrac{3}{2}\)
11 He asked his daughter what kind of sport were you interested in
12 I asked the neighboor what time your husband left for work
13) You hate watching violent films , don't you ?
14) They have just repaired the street ìn front of my house,haven't they ?
15) The first TV picture wasn't produced by Baird in 1926,did he ?
16) This kind of shoes was bought last year,didn't she
My mom asked me how your course took
The man asked me how many students in the class were there