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a) P(x)= 2x^3-2x+x^2+3x+2
P(x)= 2x^3+(-2x+3x)+x^2+2
P(x)= 2x^3+1x+x^2+2
Q(x)=4x^3-3x^2-3x+4x-3x^3+4x^2+1
Q(x)=(4x^3-3x^3)+(-3x^2+4x^2)+(-3x+4x)+1
Q(x)= 1x^3+1x^2+1x+1
b) P(-1)= 2.(-1^3)+1.(-1)+(-1^2)+2
P(-1)= -2+(-1)+1+2
P(-1)= 0
=>x=-1 là nghiệm của P(x)
Q(-1)= 1.(-1^3)+1.(-1^2)+1.(-1)+1
Q(-1)= -1+1+(-1)+1
Q(-1)= 0
=>x=-1 là nghiệm của Q(x)
c) R(x)=P(x)-Q(x)=(2x^3+1x+x^2+2)-(1x^3+1x^2+1x+1)
R(x)=P(x)-Q(x)= 2x^3+1x+1x^2+2-1x^3+1x^2+1x+1
R(x)=P(x)-Q(x)= (2x^3-1x^3)+(1x+1x)+(1x^2+1x^2)+2+1
R(x)=P(x)-Q(x)= 1x^3+2x+2x^2+2+1
=> R(x)=1x^3+2x+2x^2+2+1
ahihi mik ko chắc nha !!!!
có j thì bn kiểm phép tính lại giùm mik vì mik hay quên mấy chỗ đó nha 
a: \(\left(x+\dfrac{1}{4}\right)+\left(3x-4\right)+2\left(x-3\right)=1\)
=>\(x+\dfrac{1}{4}+3x-4+2x-6=1\)
=>\(6x-\dfrac{39}{4}=1\)
=>\(6x=1+\dfrac{39}{4}=\dfrac{43}{4}\)
=>\(x=\dfrac{43}{4}:6=\dfrac{43}{24}\)
b: \(2\left(x-3\right)=3\left(x+2\right)-x+1\)
=>\(2x-6=3x+6-x+1\)
=>2x-6=2x+7
=>-6=7(vô lý)
c: \(x\left(x+3\right)+x\left(x-2\right)=2x\left(x-1\right)\)
=>\(x^2+3x+x^2-2x=2x^2-2x\)
=>3x-2x=-2x
=>3x=0
=>x=0
d: \(\left(x-1\right)\cdot3x-2\left(x+2\right)-2x=x\left(x-1\right)\)
=>\(3x^2-3x-2x-4-2x=x^2-x\)
=>\(3x^2-7x-4-x^2+x=0\)
=>\(2x^2-6x-4=0\)
=>\(x^2-3x-2=0\)
=>\(x=\dfrac{3\pm\sqrt{17}}{2}\)
a) \(\left(2x-3\right)\left(2x+3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x-3=0\\2x+3=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=3\\2x=-3\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)
b) \(\left(x-4\right)\left(x-1\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-4=0\\x-1=0\\x-2=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=4\\x=1\\x=2\end{matrix}\right.\)
c) \(2x\left(3x-1\right)-3x\left(5+2x\right)=0\)
\(\Rightarrow x\left[2\left(3x-1\right)-3\left(5+2x\right)\right]=0\)
\(\Rightarrow x\left(6x-2-15-6x\right)\)
\(\Rightarrow-16x=0\)
\(\Rightarrow x=0\)
d) \(\left(3x-2\right)\left(3x+2\right)-4\left(x-1\right)=0\)
\(\Rightarrow9x^2-4-4x+4=0\)
\(\Rightarrow9x^2-4x=0\)
\(\Rightarrow x\left(9x-4\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\9x-4=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{4}{9}\end{matrix}\right.\)
\(a,\left(2x-3\right)\left(2x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}2x-3=0\\2x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\\ b,\left(x-4\right)\left(x-1\right)\left(x-2\right)=0\Leftrightarrow\left[{}\begin{matrix}x-4=0\\x-1=0\\x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=4\\x=1\\x=2\end{matrix}\right.\)
\(P\left(x\right)-Q\left(x\right)=\left(-2x+\frac{1}{2}x^2+3x^4-3x^2-3\right)-\left(3x^4+x^3-4x^2+1,5x^3-3x^4+2x+1\right)\\ P\left(x\right)-Q\left(x\right)=-2x+\frac{1}{2}x^2+3x^4-3x^2-3-3x^4-x^3+4x^2-1,5x^3+3x^4-2x-1\\ P\left(x\right)-Q\left(x\right)=\left(-2x-2x\right)+\left(\frac{1}{2}x^2-3x^2+4x^2\right)+\left(3x^4-3x^4+3x^4\right)+\left(-3-1\right)+\left(-x^3-1,5x^3\right)\\ P\left(x\right)-Q\left(x\right)=-4x+\frac{3}{2}x^2+3x^4-4-\frac{5}{2}x^3\)
\(R\left(x\right)+P\left(x\right)-Q\left(x\right)+x^2=2x^3-\frac{3}{2}x+1\\ \Rightarrow R\left(x\right)+\left(P\left(x\right)-Q\left(x\right)\right)+x^2=2x^3-\frac{3}{2}x+1\\ \Rightarrow R\left(x\right)-4x+\frac{3}{2}x^2+3x^4-4-\frac{5}{2}x^3+x^2=2x^3-\frac{3}{2}x+1\\ \Rightarrow R\left(x\right)-4x+\left(\frac{3}{2}x+x^2\right)+3x^4-4-\frac{5}{2}x^3=2x^3-\frac{3}{2}x+1\\ \Rightarrow R\left(x\right)-4x+\frac{5}{2}x^2+3x^4-4-\frac{5}{2}x^3=2x^3-\frac{3}{2}x+1\\ \Rightarrow R\left(x\right)=2x^3-\frac{3}{2}x+1+4x-\frac{5}{2}x^2-3x^4+4+\frac{5}{2}x^3\\ \Rightarrow R\left(x\right)=\left(2x^3+\frac{5}{2}x^3\right)+\left(\frac{-3}{2}x+4x\right)+\left(1+4\right)-\frac{5}{2}x^2-3x^4\\ \Rightarrow R\left(x\right)=\frac{9}{2}x^3+\frac{5}{2}x+5-\frac{5}{2}x^2-3x^4\)
a: A(x)+B(x)
=5x^3-2x+3x^2+2x-1
=5x^3+3x^2-1
b: A(x)-C(x)
=5x^3-2x-2x^3+3x^2-3x-1
=3x^3+3x^2-5x-1
c: M(x)=B(x)+C(x)
=3x^2+2x-1+2x^3-3x^2+3x+1
=2x^3+5x
d: B(1/3)=3*1/9+2*1/3-1=1/3+2/3-1=0
=>x=1/3 là nghiệm của B(x)
a) \(P\left(x\right)=f\left(x\right)-g\left(x\right)\)
\(P\left(x\right)=\left(2x^3+x^2-3x-4\right)-\left(-x^3+3x^2+5x-1\right)\)
\(P\left(x\right)=2x^3+x^2-3x-4+x^3-3x^2-5x+1\)
\(P\left(x\right)=2x^3+x^3+x^2-3x^2-3x-5x-4+1\)
\(P\left(x\right)=3x^3-2x^2-8x-3\)
b) \(R\left(x\right)=f\left(x\right)-h\left(x\right)\)
\(R\left(x\right)=\left(2x^3+x^2-3x-4\right)-\left(-3x^3+2x^2-x-3\right)\)
\(R\left(x\right)=2x^3+x^2-3x-4+3x^3-2x^2+x+3\)
\(R\left(x\right)=2x^3+3x^3+x^2-2x^2-3x+x-4+3\)
\(R\left(x\right)=5x^3-x^2-2x-1\)
c) Mình chưa học ạ nên không biết làm.
a)P(x)=(2x3+x2-3x-4) - (-x3+3x2+5x-1)
= 2x3+x2-3x-4 - x3-3x2-5x+1
= (2x3-x3)+(x2-3x2) +(-3x-5x)+(-4+1)
= x3-2x2-8x-3
b) R(x)=(2x3+x2-3x-4) - (-3x3+2x2-x-3)
= 2x3+x2-3x-4 - 3x3-2x2+x+3
=(2x3-3x3)+(x2-2x2)+(-3x+x)+(-4+3)
= -x3-x2-2x-1
R(x) = 2x2 + 3x - 1
- M(x) = -x3 + x2
x3 + x2 + 3x - 1
Vậy R(x) - M(x) = x3 + x2 + 3x - 1