Thực hiện phép tính:
a) M = (x - 1)(x - 2)(x + 2) - ( x - 3 ) 3 ;
b) N = (xy - 1)(xy - 2) - ( xy - 2 ) 2 .
Thực hiện phép tính:
a) (1/x + x - 2) : (1/x^2-x +1 - 3/x-1 )
\(\left(\dfrac{1}{x}+x-2\right):\left(\dfrac{1}{x^2-x}+1-\dfrac{3}{x-1}\right)\)
\(=\dfrac{x^2-2x+1}{x}:\dfrac{1+x^2-x-3x}{x\left(x-1\right)}\)
\(=\dfrac{\left(x-1\right)^2}{x}\cdot\dfrac{x\left(x-1\right)}{x^2-4x+1}=\dfrac{\left(x-1\right)^3}{x^2-4x+1}\)
Thực hiện phép tính:
a)(x – 2)(x + 3) – x(x – 5)
b) 1 / x - 2 + -2 / x + 2 + 2x - 8 / x^2 - 4
\(a,\left(x-2\right)\left(x+3\right)-x\left(x-5\right)=x^2-2x+3x-6-x^2+5x=6x-6\)
\(b,\dfrac{1}{x-2}+\dfrac{-2}{x+2}+\dfrac{2x-8}{x^2-4}=\dfrac{x+2}{\left(x-2\right)\left(x+2\right)}-\dfrac{2\left(x-2\right)}{\left(x+2\right)\left(x-2\right)}+\dfrac{2x-8}{\left(x+2\right)\left(x-2\right)}=\dfrac{x+2}{\left(x-2\right)\left(x+2\right)}-\dfrac{2x-4}{\left(x+2\right)\left(x-2\right)}+\dfrac{2x-8}{\left(x+2\right)\left(x-2\right)}=\dfrac{x+2-2x+4+2x-8}{\left(x+2\right)\left(x-2\right)}=\dfrac{x-2}{\left(x+2\right)\left(x-2\right)}=\dfrac{1}{x+2}\)
Thực hiện phép tính:
a) \({x^2}.{x^4}\); b) \(3{x^2}.{x^3}\); c) \(a{x^m}.b{x^n}\) (a ≠ 0; b ≠ 0; m, n \(\in\) N).
a) \({x^2}.{x^4} = {x^{2 + 4}} = {x^6}\).
b) \(3{x^2}.{x^3} = 3.1.{x^{2 + 3}} = 3{x^5}\).
c) \(a{x^m}.b{x^n} = a.b.{x^{m + n}}\) (a ≠ 0; b ≠ 0; m, n \(\in\) N).
Thực hiện phép tính:
a)(x+3).(x-3)-(x-2).(x+5)
b)(27x3+1):(9x2-3x+1)-(3x-19)
a) = x^2 - 9 - (x^2 + 3x - 10)
= -3x + 1
b) = 3x + 1 - 3x + 19
= 20
a: \(\left(x+3\right)\left(x-3\right)-\left(x-2\right)\left(x+5\right)\)
\(=x^2-9-x^2-3x+10\)
\(=-3x+1\)
b: \(\dfrac{27x^3+1}{9x^2-3x+1}-\left(3x-19\right)\)
\(=3x+1-3x+19\)
=20
thực hiện phép tính:a) (x-2)(x+2)-x(x-1)+8
b) (4x^3y^3-6x^2y^3+2x^2y^2):2xy
a) (x-2)(x+2)-x(x-1)+8
= x2-4-x2+x+8
= (x2-x2)+(-4+8)+x
= 4+x
b) bn viết lại đề đi:v
đọc khó quá.
Thực hiện phép tính:
a)\(\sqrt{x^2+x}=x\)
b) \(\sqrt{x^2-4x-3}=x-2\)
a: =>x>=0 và x^2+x=x^2
=>x=0
b: =>x>=2 và x^2-4x-3=x^2-4x+4
=>-3=4(loại)
\(a)ĐK:x\ge0\)
\(pt\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x^2+x=x^2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ge0\\x=0\left(tm\right)\end{matrix}\right.\)
Vậy, pt có nghiệm duy nhất là x=0
\(b)ĐK:x\ge2+\sqrt{7}\)
\(pt\Leftrightarrow\left\{{}\begin{matrix}x-2\ge0\\x^2-4x-3=(x-2)^2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\x^2-4x-3=x^2-4x+4\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\-3=4\end{matrix}\right.\)(vô lý)
Vậy pt vô nghiệm
Thực hiện phép tính:
a) \({x^5}:{x^3}\); b) \((4{x^3}):{x^2}\); c) \((a{x^m}):(b{x^n})\)(a ≠ 0; b ≠ 0; m, n \(\in\) N, m ≥ n).
a) \({x^5}:{x^3} = {x^{5 - 3}} = {x^2}\);
b) \((4{x^3}):{x^2} = (4:1).({x^3}:{x^2}) = 4x\);
c) \((a{x^m}):(b{x^n}) = (a:b).({x^m}:{x^n}) = (a:b).{x^{m - n}}\)(a ≠ 0; b ≠ 0; m, n \(\in\) N, m ≥ n).
thực hiện phép tính:
a, (2x + 1)2 - 4x (x - 1)
b, (x - 2) (x + 2) - (x - 1)2
a. \(\left(2x+1\right)^2-4x\left(x-1\right)=4x^2+4x+1-4x^2+4x=8x+1\)
b. \(\left(x-2\right)\left(x+2\right)-\left(x-1\right)^2=x^2-4-x^2+2x-1=2x-5\)
a)\((2x+1)^2-4x(x-1)=4x^2+4x+1-4x^2+4x\)
=\(8x+ 1\)
b)\((X-2)(x+2)-(x-1)^2=X^2-4-(x^2-2x+1)\)
=\(X^2-4-x^2+2x-1=2x-5\)
a: \(\left(2x+1\right)^2-4x\left(x-1\right)\)
\(=4x^2+4x+1-4x^2+4x\)
=8x+1
b: \(\left(x-2\right)\left(x+2\right)-\left(x-1\right)^2\)
\(=x^2-4-x^2+2x-1\)
=2x-5
Thực hiện phép tính:
a) (x³ + 2x² - 2x + 3) : (x + 3)
b) (x³ + x² + x + 6) : (x + 2)
\(a,=\left(x^3+3x^2-x^2-3x+x+3\right):\left(x+3\right)\\ =\left(x+3\right)\left(x^2-x+1\right):\left(x+3\right)\\ =x^2-x+1\\ b,=\left(x^3+2x^2-x^2-2x+3x+6\right):\left(x+2\right)\\ =\left(x+2\right)\left(x^2-x+3\right):\left(x+2\right)\\ =x^2-x+3\)
Thực hiện phép tính:
a) (1/x+x-2) : (1/x^2-x+1-3/x-1)
b) [x^2-2x+1/3x+(x+1)^2 - 1-2x^2+4x/x^3-1 + 1/x-1] : 2x/x^3+x
a: \(=\dfrac{x^2-2x+1}{x}:\dfrac{x-1-3x^2+3x-3}{\left(x-1\right)\left(x^2-x+1\right)}\)
\(=\dfrac{\left(x-1\right)^2}{x}\cdot\dfrac{\left(x-1\right)\left(x^2-x+1\right)}{-2x^2+4x-4}\)
\(=\dfrac{\left(x-1\right)^3\cdot\left(x^2-x+1\right)}{-2x\left(x^2-2x+2\right)}\)
b: \(=\left[\dfrac{x^2-2x+1}{x^2+x+1}+\dfrac{2x^2-4x+1}{\left(x-1\right)\left(x^2+x+1\right)}+\dfrac{1}{x-1}\right]:\dfrac{2}{x^2+1}\)
\(=\dfrac{x^3-3x^2+3x+1+2x^2-4x+1+x^2+x+1}{\left(x-1\right)\left(x^2+x+1\right)}\cdot\dfrac{x^2+1}{2}\)
\(=\dfrac{x^3+3}{\left(x-1\right)\left(x^2+x+1\right)}\cdot\dfrac{x^2+1}{2}\)