<=> x³ = x² + x + 1/3
<=> 3x³ = 3(x² + x + 1/3)
<=> 3x³ = 3x² + 3x + 1
<=> 3x³ + x³ = x³ + 3x² + 3x + 1
<=> 4x³ = (x + 1)³
<=> ³√(4x³) = ³√(x + 1)³
<=> ³√4.x = x + 1
<=> ³√4.x - x = 1
<=> x(³√4 - 1) = 1
<=> x = 1/(³√4 - 1)
l i ke nha
Cho số thực dương a,b,c thỏa mãn a+b+c=3. Chứng minh rằng
a3+8≥2(ab+bc+ca)27+19.the fraction with numerator a squared and denominator b cubed plus 8 end fraction plus the fraction with numerator b squared and denominator c cubed plus 8 end fraction plus the fraction with numerator c squared and denominator a cubed plus 8 end fraction is greater than or equal to the fraction with numerator 2 open paren a b plus b c plus c a close paren and denominator 27 end fraction plus one-nineth point12. After the accident, many people were exposed ………….radiation.
A. at B. from C. to D. with
13. Emissions of pollutants into the air can …………. changes to the climate.
A. get on B. end up C. go into D. result in
14. John hasn’t got satellite TV, so he can’t watch the game.
A. John had satellite TV, he could watch the game
B. If John had satellite TV, he could watch the game
C. If John had satellite TV, he could not watch the game
D. If John didn’t have satellite TV, he could watch the game
15. If the local people drink the contaminated water, they(have) ………….health problems.
A. will have B. have C. are having D. had
16. Grace didn’t love the nature, ………….she wasn’t happy when her group went camping in a jungle.
A. so B. and C. but D. because
17. Air ………….together with littering, is causing many problems in our cities today.
A. polluted B. pollute C. polluting D. pollution
18. …………. are chemicals that are used to kill unwated plants, such as weeds.
A. Fertilizers B. Herbicides C. Pollutants D. Pesticides
REWRITE:
1. Go ahead and you will reach the bus station.
à If ………………………………………………………..
2. Do more exercise, or you will be punished by the teacher.
à If ……………………………………………………
3. Because Simon doesn’t live near his mother, he can’t visit her often
à If ……………………………………………………….
If you walk 45 minutes at a rate 4km/h and then run for 30 minutes at a rate of 10km/h, how many kilometers will you have gone at the end of one hour and 15 minutes?
tìm x, y biết:
\(\orbr{\begin{cases}\hept{\begin{cases}\hept{\begin{cases}\\\end{cases}}\\\end{cases}}\\\end{cases}}\)\(\hept{\begin{cases}x+y=2\\xy-z^2=1\end{cases}}\)
1. Determine all pairs of integer (x;y) such that \(2xy^2+x+y+1=x^2+2y^2+xy\)
2. Let a,b,c satisfies the conditions
\(\hept{\begin{cases}5\ge a\ge b\ge c\ge0\\a+b\le8\\a+b+c=10\end{cases}}\)
Prove that \(2a^2+b^2+c^2\le38\)
3. Let a nad b satis fy the conditions
\(\hept{\begin{cases}a^3-6a^2+15a=9\\b^3-3b^2+6b=-1\end{cases}}\)
Find the value of\(\left(a-b\right)^{2014}\) ?
4. Find the smallest positive integer n such that the number \(2^n+2^8+2^{11}\) is a perfect square.
a)\(\hept{\begin{cases}2x+y=5\\x-y=1\end{cases}}\)b)\(\hept{\begin{cases}2x-3y=3\\2x+5y=5\end{cases}}\)c)\(\hept{\begin{cases}4x-5y=2\\2x-3y=0\end{cases}}\)d)\(\hept{\begin{cases}0,2x+0,3y=-0,2_{ }\\0,3x-0,2y=-0,3\end{cases}}\)e)\(\hept{\begin{cases}0,3x+0,5y=3\\1,5x-2y=1,5\end{cases}}\)GIÚP EM VỚI EM CẦN GẤP ĐÓ MN ƠI
100,45
\(\frac{1000}{\frac{ }{ }\hept{\begin{cases}\\\end{cases}}890345678\orbr{\begin{cases}\\\end{cases}}3456}\)
Giải hệ phương trình bằng phương pháp cộng
1) \(\hept{\begin{cases}2x+y=5\\3x+5y=4\end{cases}}\)
2) \(\hept{\begin{cases}x-2y=1\\3x+4y=3\end{cases}}\)
3) \(\hept{\begin{cases}x-y=3\\4x+3y=5\end{cases}}\)
4) \(\hept{\begin{cases}4x+3y=2\\2x-2y=1\end{cases}}\)
Giải hệ phương trình bằng phương pháp cộng
1) \(\hept{\begin{cases}x+y=5\\x+3y=1\end{cases}}\)
2) \(\hept{\begin{cases}3x-y=2\\x+y=6\end{cases}}\)
3) \(\hept{\begin{cases}x+2y=5\\3x-2y=3\end{cases}}\)
4) \(\hept{\begin{cases}2x-y=5\\2x+3y=1\end{cases}}\)
