Thực hiện phép chia:
[7(x-y)5+6(y-x)4-2(x-y)3+(y-x)2 ]:(x-y)2
thực hiện phép chia
a (4x^5-8x^3):(-2x^3)
b(9x^3-12x^2 + 3x ) : (-3x)
c (xy^2 + 4x^2y^3 -3x^2y^4):(-1/2x^2y^3)
d[2(x-y)^3-7(y-x)^2 - (y-x)] : (x-y)
e[(x^3 - y) ^5 -2(x-y)^4 + 3(x-y)^2] :[5(x-y)^2]
Thực hiện phép tính :
Thực hiện phép tính :
5.x^2(x-y+1)+(x^2-1)(x+y)
Bài 2:
1: \(A=\left(x+2\right)\left(x^2-2x+4\right)+2\left(x+1\right)\left(1-x\right)\)
\(=\left(x+2\right)\left(x^2-x\cdot2+2^2\right)-2\left(x+1\right)\left(x-1\right)\)
\(=x^3+2^3-2\left(x^2-1\right)\)
\(=x^3+8-2x^2+2=x^3-2x^2+10\)
\(B=\left(2x-y\right)^2-2\left(4x^2-y^2\right)+\left(2x+y\right)^2+4\left(y+2\right)\)
\(=\left(2x-y\right)^2-2\cdot\left(2x-y\right)\left(2x+y\right)+\left(2x+y\right)^2+4\left(y+2\right)\)
\(=\left(2x-y-2x-y\right)^2+4\left(y+2\right)\)
\(=\left(-2y\right)^2+4\left(y+2\right)\)
\(=4y^2+4y+8\)
2: Khi x=2 thì \(A=2^3-2\cdot2^2+10=8-8+10=10\)
3: \(B=4y^2+4y+8\)
\(=4y^2+4y+1+7\)
\(=\left(2y+1\right)^2+7>=7>0\forall y\)
=>B luôn dương với mọi y
Bài 1:
5: \(x^2\left(x-y+1\right)+\left(x^2-1\right)\left(x+y\right)\)
\(=x^3-x^2y+x^2+x^3+x^2y-x-y\)
\(=2x^3-x+x^2-y\)
6: \(\left(3x-5\right)\left(2x+11\right)-6\left(x+7\right)^2\)
\(=6x^2+33x-10x-55-6\left(x^2+14x+49\right)\)
\(=6x^2+23x-55-6x^2-84x-294\)
=-61x-349
Bài 1 thực hiện phép tính
a ) 8/15 . 7/13 +8/15 . 6/13
b ) 3/4 + -7/12 - 2/3
Bài 2 Tìm x biết
x /2, 7= -2/3, 6
Bài 3 tìm x , y biết
x/2 = y/5 và x + y = -21
Bài 1:
a) \(=\dfrac{8}{15}\left(\dfrac{7}{13}+\dfrac{6}{13}\right)=\dfrac{8}{15}.1=\dfrac{8}{15}\)
b) \(=\dfrac{3.3-7-2.4}{12}=-\dfrac{6}{12}=-\dfrac{1}{2}\)
Bài 2:
\(\dfrac{x}{2,7}=-\dfrac{2}{3,6}\Rightarrow x=\dfrac{\left(-2\right).2,7}{3,6}\Rightarrow x=-\dfrac{3}{2}\)
Bài 3:
\(\dfrac{x}{2}=\dfrac{y}{5}=\dfrac{x+y}{2+5}=-\dfrac{21}{7}=-3\)
\(\Rightarrow\left\{{}\begin{matrix}x=\left(-3\right).2=-6\\y=\left(-3\right).5=-10\end{matrix}\right.\)
Bài 3:
3: \(6x\left(x-y\right)-9y^2+9xy\)
\(=6x\left(x-y\right)+9xy-9y^2\)
\(=6x\left(x-y\right)+9y\left(x-y\right)\)
\(=\left(x-y\right)\left(6x+9y\right)\)
\(=3\left(2x+3y\right)\left(x-y\right)\)
Bài 4:
Thực hiện các phép chia:
a) \(\left( {4{x^3}{y^2} - 8{x^2}y + 10xy} \right):\left( {2xy} \right)\) b) \(\left( {7{x^4}{y^2} - 2{x^2}{y^2} - 5{x^3}{y^4}} \right):\left( {3{x^2}y} \right)\)
`a, (4x^3y^2 - 8x^2y + 10xy) : 2xy`
`= 2x^2y - 4x + 5`.
`b, 7x^4y^2 - 2x^2y^2 - 5x^3y^4 : 3x^2y`
`= 7/3 x^2y - 3/2y - 5/3xy^3`
Thực hiện phép chia:
a) (x-y)^5:(y-x)^3
b) [3:(x-y)^5-2(x-y)^4+3(x-y)^2]:[5(x-y)^2]
c) (3y-6x)^3:9(2x-y)
Helpppppppp QvQ
Thực hiện phép chia \(8{x^4}{y^5}{z^3}\) cho \(2{x^3}{y^4}z\).
`8x^4y^5z^3 : 2x^3y^4z`
`= 4xyz^2`.
Thực hiện mỗi phép tính sau:
a) \({x^2} + \dfrac{1}{4}{x^2} - 5{x^2}\);
b) \({y^4} + 6{y^4} - \dfrac{2}{5}{y^4}\).
a) \({x^2} + \dfrac{1}{4}{x^2} - 5{x^2} = (1 + \dfrac{1}{4} - 5){x^2} = - \dfrac{{15}}{4}{x^2}\);
b) \({y^4} + 6{y^4} - \dfrac{2}{5}{y^4} = (1 + 6 - \dfrac{2}{5}){y^4} = \dfrac{{33}}{5}{y^4}\).
3. Thực hiện phép tính:
a. 5/(2x ^ 2 * y) + 2/(3xy) - y/(x ^ 3)
b. (2x - 7)/(10x - 4) - (3x + 5)/(4 - 10x)
c. x ^ 2 + 1 - (x ^ 4 - 3x ^ 2)/(x ^ 2 - 1)
a: \(=\dfrac{5}{2x^2y}+\dfrac{2}{3xy}-\dfrac{y}{x^3}\)
\(=\dfrac{5\cdot3\cdot x}{6x^3y}+\dfrac{2\cdot2\cdot x^2}{6x^3y}-\dfrac{6y^2}{6x^3y}\)
\(=\dfrac{15x+4x^2-6y^2}{6x^3y}\)
b: \(=\dfrac{2x-7+3x+5}{10x-4}=\dfrac{5x-2}{10x-4}=\dfrac{1}{2}\)
c: \(=\dfrac{x^4-1-x^4+3x^2}{x^2-1}=\dfrac{3x^2-1}{x^2-1}\)