giúp e vs mn oii 🥲🙃
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ST
1
DT
Đỗ Thanh Hải
CTVVIP
28 tháng 7 2021
1 They donate clothes
2 They take care of childrens
3 They work in an orphanage
4 They teach them
5 I think we need to do community service
because we can help many people
HQ
Hà Quang Minh
Giáo viên
24 tháng 7 2023
\(x:y:z=\dfrac{4}{7}:\dfrac{5}{8}:\dfrac{9}{10}=160:175:252\)
4 tháng 1 2024
\(4x^4+1\)
\(=4x^4+4x^2+1-4x^2\)
\(=\left(2x^2+1\right)^2-\left(2x\right)^2\)
\(=\left(2x^2+1+2x\right)\left(2x^2+1-2x\right)\)
NV
Nguyễn Việt Lâm
Giáo viên
4 tháng 1 2024
\(4x^4+1=4x^4+4x^2+1-4x^2=\left(2x^2+1\right)^2-\left(2x\right)^2\)
\(=\left(2x^2-2x+1\right)\left(2x^2+2x+1\right)\)
14 tháng 11 2023
e: \(\dfrac{x^2+3x+9}{x^3+4x^2+4x}\cdot\dfrac{x^2+2x}{x^3-27x}\)
\(=\dfrac{x^2+3x+9}{x\left(x^2+4x+4\right)}\cdot\dfrac{x\left(x+2\right)}{x\left(x^2-27\right)}\)
\(=\dfrac{x^2+3x+9}{\left(x+2\right)^2}\cdot\dfrac{x+2}{x\left(x^2-27\right)}\)
\(=\dfrac{\left(x^2+3x+9\right)}{\left(x+2\right)\cdot x\left(x^2-27\right)}\)
f: \(\dfrac{2x^2+4xy+2y^2}{5x-5y}\cdot\dfrac{15x-15y}{2x^3+2y^3}\)
\(=\dfrac{2\left(x^2+2xy+y^2\right)}{5\left(x-y\right)}\cdot\dfrac{15\left(x-y\right)}{2\left(x^3+y^3\right)}\)
\(=\dfrac{\left(x+y\right)^2}{1}\cdot\dfrac{3}{\left(x+y\right)\left(x^2-xy+y^2\right)}\)
\(=\dfrac{3\left(x+y\right)}{x^2-xy+y^2}\)
g: \(\dfrac{x^3-4x}{x^2-7x+12}\cdot\dfrac{x-4}{x^2-2x}\)
\(=\dfrac{x\left(x^2-4\right)}{\left(x-3\right)\left(x-4\right)}\cdot\dfrac{x-4}{x\left(x-2\right)}\)
\(=\dfrac{x^2-4}{\left(x-3\right)\left(x-2\right)}=\dfrac{\left(x-2\right)\left(x+2\right)}{\left(x-3\right)\left(x-2\right)}=\dfrac{x+2}{x-3}\)
T
1
SV
Sinh Viên NEU
CTVVIP
15 tháng 11 2023
1 If we continue polluting the air, the environment will be affected seriously
2 If we don't stop damaging birds' homes, there will be fewer birds left
3 If we continue polluting the water, there will be more disease in people and animals
4 If we keep polluting the land, the soil will not be safe enough for us to grow food in
5 If we use public transportation when we need, there will be less air pollution
12 Daniel signs up for a clean-up campaign so that he can join in it
13 People in my neighborhood clean the park up so that their children will have a nice place to play
14 Almost all the students in my school plant trees so that they can have much fresher air
5 tháng 8 2023
m: \(=x^m\cdot x^2-x^m=x^m\left(x^2-1\right)=x^m\left(x-1\right)\left(x+1\right)\)
n: \(=5\cdot x^m\cdot x^2+10x^2\)
\(=5x^2\left(x^m+2\right)\)
o: \(=5x\left(x-2y\right)+2\left(x-2y\right)^2\)
\(=\left(x-2y\right)\left(5x+2x-4y\right)\)
=(x-2y)(7x-4y)
p: \(=7x\left(y-4\right)^2+\left(y-4\right)^3\)
\(=\left(y-4\right)^2\cdot\left(7x+y-4\right)\)
q: \(\left(4x-8\right)\left(x^2+6\right)-\left(4x-8\right)\left(x+7\right)+9\left(8-4x\right)\)
\(=\left(4x-8\right)\left(x^2+6-x-7\right)-9\left(4x-8\right)\)
\(=\left(4x-8\right)\left(x^2-x-10\right)\)
\(=4\left(x-2\right)\left(x^2-x-10\right)\)
P
Phong
CTVHS
5 tháng 8 2023
m) \(x^{m+2}-x^m\)
\(=x^m\cdot x^2-x^m\)
\(=x^m\left(x^2-1\right)\)
\(=x^m\left(x^2-1^2\right)\)
\(=x^m\left(x-1\right)\left(x+1\right)\)
n) \(5x^{m+2}+10x^2\)
\(=5x^m\cdot x^2+10x^2\)
\(=5x^2\cdot x^m+10x^2\)
\(=5x^2\left(x^m+2\right)\)
o) \(5x\left(x-2y\right)+2\left(2y-x\right)^2\)
\(=5x\left(x-2y\right)+2\left(x-2y\right)^2\)
\(=\left(x-2y\right)\left[5x+2\left(x-2y\right)\right]\)
\(=\left(x-2y\right)\left(5x+2x-4y\right)\)
\(=\left(x-2y\right)\left(7x-4y\right)\)
p) \(7x\left(y-4\right)^2-\left(4-y\right)^3\)
\(=7x\left(4-y\right)^2-\left(4-y\right)^3\)
\(=\left(4-y\right)^2\left[7x-\left(4-y\right)\right]\)
\(=\left(4-y\right)^2\left(7x-4+y\right)\)
q) \(\left(4x-8\right)\left(x^2+6\right)-\left(4x-8\right)\left(x+7\right)+9\left(8-4x\right)\)
\(=4\left(x-2\right)\left(x^2+6\right)-4\left(x-2\right)\left(x+7\right)-36\left(x-2\right)\)
\(=4\left(x-2\right)\left[\left(x^2+6\right)-\left(x+7\right)-9\right]\)
\(=4\left(x-2\right)\left(x^2+6-x-7-9\right)\)
\(=4\left(x-2\right)\left(x^2-x-10\right)\)
30 tháng 7 2020
\(\frac{17,8.3,7-7,8.4,8+5,7.17,8-4,6.7,8}{11,2+12,3+13,4-12,6-11,5-10,4}\)
\(=\frac{17,8\left(3,7+5,7\right)-7,8\left(4,8+4,6\right)}{\left(13,4-12,6\right)+\left(12,3-11,5\right)+\left(11,2-10,4\right)}\)
\(=\frac{17,8.9,4-7,8.9,4}{0,8+0,8+0,8}\)
\(=119,1\)
f: \(F=\sqrt[3]{4+\frac53\cdot\sqrt{\frac{31}{3}}}+\sqrt[3]{4-\frac53\cdot\sqrt{\frac{31}{3}}}\)
=>\(F^3=4+\frac53\cdot\sqrt{\frac{31}{3}}+4-\frac53\cdot\sqrt{\frac{31}{3}}+3\cdot F\cdot\sqrt[3]{\left(4+\frac53\sqrt{\frac{31}{3}}\right)\left(4-\frac53\cdot\sqrt{\frac{31}{3}}\right)}\)
=>\(F^3=8+3\cdot F\cdot\sqrt[3]{16-\frac{25}{9}\cdot\frac{31}{3}}=8+3F\cdot\sqrt[3]{-\frac{343}{27}}=8-7F\)
=>\(F^3+7F-8=0\)
=>\(F^3-F^2+F^2-F+8F-8=0\)
=>\(\left(F-1\right)\left(F^2+F+8\right)=0\)
=>F-1=0
=>F=1
o: \(\sqrt[3]{6\sqrt3-10}=\sqrt[3]{3\sqrt3-3\cdot\left(\sqrt3\right)^2\cdot1+3\cdot\sqrt3\cdot1^2-1}=\sqrt[3]{\left(\sqrt3-1\right)^3}=\sqrt3-1\)
\(\sqrt{2+\sqrt3}=\frac{\sqrt{4+2\sqrt3}}{\sqrt2}=\frac{\sqrt{\left(\sqrt3+1\right)^2}}{\sqrt2}=\frac{\sqrt3+1}{\sqrt2}\)
\(X=\sqrt{2+\sqrt3}-\sqrt{\frac{\sqrt[3]{6\sqrt3-10}}{\sqrt3+1}}=\frac{\sqrt3+1}{\sqrt2}-\sqrt{\frac{\sqrt3-1}{\sqrt3+1}}\)
\(=\frac{\sqrt3+1}{\sqrt[2]{2}}-\sqrt{\frac{\left(\sqrt3-1\right)\left(\sqrt3+1\right)}{\left(\sqrt3+1\right)^2}}=\frac{\sqrt3+1}{\sqrt2}-\sqrt{\frac{2}{\left(\sqrt3-1\right)^2}}\)
\(=\frac{\sqrt3+1}{\sqrt2}-\frac{\sqrt2}{\sqrt3+1}=\frac{\left(\sqrt3+1\right)^2-2}{\sqrt2\left(\sqrt3+1\right)}=\frac{4+2\sqrt3-2}{\sqrt2\left(\sqrt3+1\right)}=\frac{2\sqrt3+2}{\sqrt2\left(\sqrt3+1\right)}\)
\(=\frac{2\left(\sqrt3+1\right)}{\sqrt2\left(\sqrt3+1\right)}=\frac{2}{\sqrt2}=\sqrt2\)
p: \(K=\frac{\left(\sqrt3-1\right)\cdot\sqrt[3]{10+6\sqrt3}}{\sqrt{21+4\sqrt5}+3}=\frac{\left(\sqrt3-1\right)\cdot\sqrt[3]{3\sqrt3+3\cdot\left(\sqrt3\right)^2\cdot1+3\cdot\sqrt3\cdot1^2+1^3}}{\left(\sqrt{\left(2\sqrt5+1\right)^2}\right)+3}\)
\(=\frac{\left(\sqrt3-1\right)\cdot\sqrt[3]{\left(\sqrt3+1\right)^2}}{2\sqrt5+1+3}=\frac{\left(\sqrt3-1\right)\left(\sqrt3+1\right)}{2\sqrt5+4}=\frac{2}{2\sqrt5+4}=\frac{1}{\sqrt5+2}=\sqrt5-2\)
q: \(Q=\sqrt[3]{55+\sqrt{3024}}+\sqrt[3]{55-\sqrt{3024}}\)
=>\(Q^3=55+\sqrt{3024}+55-\sqrt{3024}+3\cdot Q\cdot\sqrt[3]{\left(55-\sqrt{3024}\right)\left(55+\sqrt{3024}\right)}\)
=>\(Q^3=110+3\cdot Q\cdot\sqrt[3]{3025-3024}=110+3Q\)
=>\(Q^3-3Q-110=0\)
=>\(Q^3-5Q^2+5Q^2-25Q+22Q-110=0\)
=>\(\left(Q-5\right)\left(Q^2+5\cdot Q+22\right)=0\)
=>Q-5=0
=>Q=5