Giúp mik vơi mik cân gấp
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1 were - would you play
2 weren't studying - would have
3 had taken - wouldn't have got
4 would you go - could
5 will you give - is
6 recycle - won't be
7 had heard - wouldn't have gone
8 would you buy - had
9 don't hurry - will miss
10 had phoned - would have given
11 were - wouldn't eat
12 will go - rains
13 had known - would have sent
14 won't feel - swims
15 hadn't freezed - would have gone
`@` `\text {Ans}`
`\downarrow`
`4,`
Vì `\text {MN // BC}`
`=>` $\widehat {B} = \widehat {BMN} = 114^0 (\text {2 góc đối đỉnh})$
Ta có: \(\left\{{}\begin{matrix}\widehat{\text{BMN}}+\widehat{\text{AMN}}=180^0\left(\text{2 góc kề bù}\right)\\\widehat{\text{CNM}}+\widehat{\text{ANM}}=180^0\left(\text{2 góc kề bù}\right)\end{matrix}\right.\)
`=>`\(\left\{{}\begin{matrix}\widehat{\text{AMN}}=180^0-114^0=66^0\\\widehat{\text{ANM}}=180^0-130^0=50^0\end{matrix}\right.\)
Xét `\Delta AMN`:
\(\widehat{\text{A}}+\widehat{\text{M}}+\widehat{\text{N}}=180^0\left(\text{định lý tổng 3 góc trong 1 tgiac}\right)\)
`=>`\(\widehat{\text{A}}+66^0+50^0=180^0\)
`=>`\(\widehat{\text{A}}=180^0-66^0-50^0=64^0\)
Mà \(\widehat{\text{A}}=\widehat{\text{x}}\)
`=>`\(\widehat{\text{x}}=64^0\)
Vậy, số đo của góc `x = 64^0.`
Bài 2:
b: Gọi (d'): y=ax+b
Vì (d')//(D) nên a=2
hay y=2x+b
Thay x=-1 và y=2 vào y=2x+b, ta được:
\(2\cdot\left(-1\right)+b=2\)
\(\Leftrightarrow b=0\)
Vậy: y=2x
a, Trọng lượng vật là \(P=10m=50.10=500\left(N\right)\)
40 cm = 0,4(m)
Công thực hiện là
\(A=P.h=500.0,4=0,2\left(KJ\right)\)
Lực kéo vật khi dùng mặt phẳng nghiêng là
\(F=\dfrac{A}{l}=\dfrac{200\left(KJ\rightarrow J\right)}{2}=100\left(N\right)\)
b, Công thực hiện vật khi có ma sát là
\(A'=\dfrac{A}{80\%}.100\%=\dfrac{200}{80}.100=250\left(J\right)\)
Lực kéo vật lúc này là
\(F_k=\dfrac{A}{s}=\dfrac{500}{2}=250\left(N\right)\)
Công do lực ma sát sinh ra là
\(A_{ms}=A-A_i=A-H.A=200-80\%.200=40\left(J\right)\)
Độ lớn lực ma sát là
\(A_{ms}=F_{ms}.s\Rightarrow F_{ms}=\dfrac{A_{ms}}{s}\\ \)
\(=\dfrac{40}{2}=20\left(N\right)\)
a: \(=\left(-\dfrac{3}{5}+\dfrac{-4}{5}+\dfrac{7}{5}\right)+\dfrac{1}{3}=\dfrac{1}{3}\)
b: \(=\dfrac{-3}{17}+\dfrac{2}{3}+\dfrac{3}{17}=\dfrac{2}{3}\)
e: \(=\dfrac{-5}{21}-\dfrac{16}{21}+1=0\)
g: \(=\dfrac{-4}{11}\cdot\dfrac{-11}{4}\cdot\dfrac{1}{3}=\dfrac{1}{3}\)
h: \(=\dfrac{7}{36}+\dfrac{8}{9}-\dfrac{2}{3}=\dfrac{7}{36}+\dfrac{32}{36}-\dfrac{24}{36}=\dfrac{15}{36}=\dfrac{5}{12}\)
i: \(=\dfrac{4}{7}-\dfrac{5}{8}-\dfrac{3}{28}=\dfrac{32}{56}-\dfrac{35}{56}-\dfrac{6}{56}=\dfrac{-9}{56}\)

giúp mik với ạ mik cần gấp. GIẢI CỤ THỂ GIÚP MIK vs ạ





1: \(\frac{15}{34}+\frac{7}{21}+\frac{19}{34}-\frac{20}{15}=\left(\frac{15}{34}+\frac{19}{34}\right)+\left(\frac13-\frac43\right)=1-1=0\)
2: \(2\frac56+\frac16:\left(-\frac58\right)=\frac{17}{6}+\frac16\cdot\frac{-8}{5}=\frac{17}{6}-\frac{8}{30}=\frac{85-8}{30}=\frac{77}{30}\)
3: \(3-\frac32+\frac14-1\frac15=\frac32+\frac14-\frac65\)
\(=\frac{30}{20}+\frac{5}{20}-\frac{24}{20}=\frac{35-24}{20}=\frac{11}{20}\)
4: \(5^3:25+2^4:4=\frac{125}{25}+\frac{16}{4}=5+4=9\)
5: \(23\frac14:\frac75-13\frac14:\frac75=\left(23+\frac14-13-\frac14\right):\frac75=10\cdot\frac57=\frac{50}{7}\)
6: \(12\frac15\cdot\frac45-22\frac15\cdot\frac45=\left(12+\frac15-22-\frac15\right)\cdot\frac45=-10\cdot\frac45=-8\)
7: \(\left(-2\right)^2+\sqrt{49}-\sqrt{16}+\sqrt{25}=4+7-4+5=7+5=12\)
8: \(\frac45-\left(-\frac12\right)^2=\frac45-\frac14=\frac{16}{20}-\frac{5}{20}=\frac{11}{20}\)
9: \(5-\left(-\frac57\right)^0+\left(\frac13\right)^2:3=5-1+\frac{1}{27}=4+\frac{1}{27}=\frac{109}{27}\)
10: \(\frac29\left(\frac52-\frac34\right)=\frac29\left(\frac{10}{4}-\frac34\right)=\frac29\cdot\frac74=\frac{7}{9\cdot2}=\frac{7}{18}\)
11: \(16\cdot\left(-\frac14\right)^3-\frac12=16\cdot\frac{-1}{64}-\frac12=-\frac14-\frac12=-\frac34\)