đó bạn nè :

Châu Nam CỰC có đặc điểm gì nổi bật

Câu 1:

a) \(\left(-\dfrac{2}{17}x^3y^5\right).\dfrac{34}{5}x^2y=\left(-\dfrac{2}{17}.\dfrac{34}{5}\right).\left(x^3.x^2\right).\left(y^5.y\right)=-\dfrac{4}{5}x^5y^6\)

b) \(7x^2y^4+\dfrac{-1}{5}x^2y^4-3x^2y^4=\left(7+\dfrac{-1}{5}-3\right)x^2y^4=\dfrac{19}{5}x^2y^4\)

Câu 3:

a. \(P\left(x\right)=2x^3-2x+x^2-x^3+3x+2\)

\(=\left(2x^3-x^3\right)+x^2+\left(-2x+3x\right)+2\)

\(=x^3+x^2+x+2\)

\(Q\left(x\right)=3x^3-4x^2+3x-4x-4x^3+5x^2+1\)

\(=\left(3x^3-4x^3\right)+\left(-4x^2+5x^2\right)+\left(3x-4x\right)+1\)

\(=-x^3+x^2-x+1\)

b. \(M\left(x\right)=P\left(x\right)+Q\left(x\right)=\left(x^3+x^2+x+2\right)+\left(-x^3+x^2-x+1\right)\)

\(=\left(x^3-x^3\right)+\left(x^2+x^2\right)+\left(x-x\right)+\left(2+1\right)\)

\(=2x^2+3\)

\(N\left(x\right)=P\left(x\right)-Q\left(x\right)=\left(x^3+x^2+x+2\right)-\left(-x^3+x^2-x+1\right)\)

\(=\left(x^3+x^3\right)+\left(x^2-x^2\right)+\left(x+x\right)+\left(2-1\right)\)

\(=2x^3+2x+1\)

c. \(M\left(x\right)=2x^2+3=0\)

\(\Rightarrow2x^3=-3\)

\(\Rightarrow x^2=-\dfrac{3}{2}\)

Mà \(x^2\ge0\Rightarrow x\in\varnothing\)

Vậy \(M\left(x\right)\) không có nghiệm.

Câu 4:

\(P\left(x\right)=ax^2+5x-3\)

\(\Rightarrow P\left(\dfrac{1}{2}\right)=a.\left(\dfrac{1}{2}\right)^2+5.\dfrac{1}{2}-3\)

\(=a.\dfrac{1}{4}+\dfrac{5}{2}-3\)

\(=\dfrac{a}{4}+\dfrac{5-2.3}{2}\)

\(=\dfrac{a}{4}-\dfrac{1}{2}\)

Theo đề ra: \(P\left(x\right)\) có nghiệm là \(\dfrac{1}{2}\)

\(\Rightarrow P\left(\dfrac{1}{2}\right)=0\Leftrightarrow\dfrac{a}{4}-\dfrac{1}{2}=0\)

\(\Rightarrow\dfrac{a}{4}=\dfrac{1}{2}\)

\(\Rightarrow a=\dfrac{4}{2}=2\)

1604cm

16 m 4 cm = 1604 cm

                  = 16,04 m

  Chúc bạn học tốt~

\(x:5=15035\) (dư 8)

\(x=5\times15035+8\)

\(x=75183\)

X = 15035 x 5 + 8 = 75183

mn ơi giúp mình bài này với

5/7 x 11/13 x 26 = 5/7 x 11 x 2 = 110/7

muốn bị báo cáo không

gì thế

\(\left(x-305\right)\times7=26728+19640\\ \left(x-305\right)\times7=46368\\ x-305=46368:7\\ x-305=6624\\ x=6624+305\\ x=6929\)

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