mn giúp mk bài mk mk đăng 1 phút trc đk ạ??
mk camon trc ạ:333(bài tiếng anh ạ)
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LN
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mn giúp mk nha.....camon trc ạ
LN
có cả lý vs hóa nha mn tại mk k tìm thấy KHTN á...mn giúp mk nha....camon trc ạ
3
24 tháng 12 2022
bạn ơi, bạn chia nhỏ ra để hỏi nha! Vì các bài sau đây để làm hết trình bày sẽ lâu lắm ah!
HH
11 tháng 1 2023
câu 17
Lập công thức hóa học của hợp chất; \(Cu_x\)\(S_y\)\(O_z\)
Khối lượng phân tử của hợp chất; 64.x+32.y+16.z = 160 amu
Lập công thức để tìm x,y,z
%O trong hợp chất là; O= 100-(40+20)=> 40%
Cu= \(\dfrac{64.x.100\%}{160}\)=40% => x = \(\dfrac{160.40\%}{64.100}\)=1 amu
S= \(\dfrac{32.y.100\%}{160}\)=20% => y = \(\dfrac{160.20\%}{32.100}\)=1 amu
O= \(\dfrac{16.x.100\%}{160}\)=40% => z = \(\dfrac{160.40\%}{16.100}\)= 4 amu
Công thức hóa học của hợp chất là \(CuSO_4\)
giúp mk mí...mk camon trc ạ
23 tháng 2 2023
Bài 3:
a: Bậc là 7
b: Bậc là 5
c: Bậc là 2
d: Bậc là 4
e: Bậc là 2
f: Bậc là 9
g: bậc là 1
h: bậc là 0
PT
9 tháng 2 2021
Today, there are many hot issues that are being paid great attention by the whole society such as education, food safety and hygiene, continuous evils and especially traffic safety issues. Today's presentation will give you an understanding of this field. Traffic is the movement between vehicles such as motorcycles, cars, ships, planes ... on different distances, types of roads such as roads, railways, airways ... Participation and regulation of traffic Information is not easy because the amount of traffic is increasing, especially roads. The current traffic situation is ringing an urgent bell about human consciousness. One day, in Vietnam, there are dozens of accidents, even very serious accidents, especially on peak occasions such as festivals or Lunar New Year. Recently, public opinion is very pity for the strawberry caravan incident with eleven people killed. The joy of the whole family line suddenly turned into pain, the disaster struck everyone. One thing that is making us very indignant is the container incident that caused the catastrophic accident for people who stopped red lights. It is special that the driver has been confirmed to be positive for drugs. All someone's passing away from a traffic accident ultimately comes from the irresponsibility, indifference, and disregard for the lives of such people. Traffic accident not only kills a human's life, the biggest loss, but also causes great damage to material possessions. This is damaging to the economy, social disorder, making people worried and insecure and inhibiting the development of our country. Above all, the relatives of the ill-fated victims will suffer lasting damage, forever the scar that will never disappear. Therefore, ensuring traffic safety is very important and urgent. Everything works only when it comes from one's own consciousness. Let's obey the law when entering traffic from the smallest actions such as wearing a helmet, stopping the red light, not exceeding speed ... This will help you largely avoid the risk of having an unfortunate incident. However, you should also remember that helmets must be quality helmets, must be fitted with straps to take advantage of its effect. If you stop the red light, you must wait for the green light to go, not "one second fast, a lifetime slow" ... Besides, we also need to regularly organize propaganda activities to guide people to participate in communication. information properly, especially with the student's age. The concerned authorities, especially the traffic police forces, have to constantly patrol, control and frankly handle violation situations to set an example. Traffic safety is your way to contribute to society. It is not always economic support or charitable donations that help the country develop. First of all, you should be consciously protecting your life when in traffic. It's how you love yourself and keep others from worrying about you. And people have everything. Your body is cold, healthy is still abundant, you can work, make a lot of money and fulfill your dreams.
14 tháng 8 2023
14:
a: \(A=\dfrac{15x^5y^3-10x^3y^2+20x^4y^4}{5x^2y^2}\)
\(=\dfrac{5x^2y^2\left(3x^3y-10x+4x^2y^2\right)}{5x^2y^2}=3x^3y-10x+4x^2y^2\)
Khi x=-1 và y=2 thì \(A=3\left(-1\right)^3\cdot2-10\cdot\left(-1\right)+4\cdot\left(-1\cdot2\right)^2\)
\(=-6+10+4\cdot4=4+16=20\)
b: \(B=\dfrac{4x^4y^2+3x^4y^3-6x^3y^2}{x^2y^2}=4x^2+3x^2y-6x\)
Khi x=y=-2 thì \(B=4\cdot\left(-2\right)^2+3\cdot\left(-2\right)^2\left(-2\right)-6\left(-2\right)\)
\(=16+12-6\cdot4=28-24=4\)
c: \(C=\dfrac{\dfrac{2}{3}xy\left(-3xy+6-9y^2\right)}{\dfrac{2}{3}xy}=-3xy+6-9y^2\)
Khi x=1/2 và y=4 thì \(C=-3\cdot\dfrac{1}{2}\cdot4+6-9\cdot4^2\)
=-6+6-9*16
=-144
d: \(D=\dfrac{x^2y^2\left(\dfrac{1}{3}y^3-\dfrac{2}{3}x^3\right)}{2x^2y^2}=\dfrac{1}{6}y^3-\dfrac{1}{3}x^3\)
Khi x=-3 và y=3 thì \(D=\dfrac{-1}{3}\left(-3\right)^3-\dfrac{1}{6}\cdot3^3\)
=9-9/2
=9/2
e: \(E=\dfrac{5x^2y\left(4x^3y^3+2xy-y^2\right)}{5x^2y}=4x^3y^3+2xy-y^2\)
Khi x=1 và y=-1 thì \(E=-4-2-1=-7\)
f: G\(=\dfrac{x^2yz\left(7x^3y^3z^2-3x^2z+2y\right)}{x^2yz}=7x^3y^3z^2-3x^2z+2y\)
Khi x=-1;y=1;z=2 thì \(G=7\cdot\left(-1\cdot1\right)^3\cdot2^2-3\cdot\left(-1\right)^2\cdot2+2\cdot1\)
=-7*4-6+2
=-28-4=-32
NT
7
9 tháng 7 2018
a) (a + b + c)2 = [(a + b) + c]2 = (a + b)2 + 2(a + b)c + c2
= a2+ 2ab + b2 + 2ac + 2bc + c2
= a2 + b2 + c2 + 2ab + 2bc + 2ac.
b) (a + b – c)2 = [(a + b) – c]2 = (a + b)2 - 2(a + b)c + c2
= a2 + 2ab + b2 - 2ac - 2bc + c2
= a2 + b2 + c2 + 2ab - 2bc - 2ac.
c) (a – b –c)2 = [(a – b) – c]2 = (a – b)2 – 2(a – b)c + c2
= a2 – 2ab + b2 – 2ac + 2bc + c2
= a2 + b2 + c2 – 2ab + 2bc – 2ac.
bài này phải không nếu đúng thì tích hộ mình
PL
1
27 tháng 9 2021
Ta có: \(x^2=20x-100\)
\(\Leftrightarrow x^2-20x+100=0\)
\(\Leftrightarrow x-10=0\)
hay x=10
