thực hiện phép chia: \(\left(x^3+2x^2-2x-1\right):\left(x^2+3x+1\right)\)
Thực hiện phép tính:
a) \(2x.\left(2x^2+3x-1\right)\)
b) \(\left(x+5\right).\left(2x-3\right)\)
c) \(\left(x+1\right)^2-x\left(2+3x\right)\)
d) \(\left(2x^3+x^2-8x+3\right):\left(2x-3\right)\)
b: \(=2x^2-3x+10x-15=2x^2+7x-15\)
Thực hiện phép tính:
a) \(3x.\left(2x^2-3x+4\right)\)
b) \(\left(x+3\right)^2+\left(3x-2\right)\left(x+4\right)\)
c) \(\dfrac{2x-4}{x-1}+\dfrac{2x+2}{x^2-1}\)
`a)3x(2x^2-3x+4)`
`=6x^3-9x^2+12x`
______________________________________________
`b)(x+3)^2+(3x-2)(x+4)`
`=x^2+6x+9+3x^2+12x-2x-8`
`=4x^2+16x+1`
______________________________________________
`c)[2x-4]/[x-1]+[2x+2]/[x^2-1]` `ĐK: x \ne +-1`
`=[(2x-4)(x+1)+2x+2]/[(x-1)(x+1)]`
`=[2x^2+2x-4x-4+2x+2]/[(x-1)(x+1)]`
`=[2x^2-2]/[x^2-1]`
`=2`
Bài 1 : Ko thực hiện phép chia , hãy xem phép chia sau đây có là phép chia hết ko và tìm đa thức dư trong trg hợp ko chia hết :
a) \(\left(x^3+2x^2-3x+9\right):\left(x+3\right)\)
b) \(\left(9x^4-6x^3+15x^2+2x+1\right):\left(3x^2-2x+5\right)\)
b)\(\frac{9x^4-6x^3+15x^2+2x+1}{3x^2-2x+5}=\frac{3x^2.\left(3x^2-2x+5\right)+2x+1}{3x^2-2x+5}=3x^2+\frac{2x+1}{3x^2-2x+5}\)
=> đa thức dư trong phép chia là 2x+1
\(\frac{x^3+2x^2-3x+9}{x+3}=\frac{x^3+9x^2+27x+27-7x^2-30x-18}{x+3}=\frac{\left(x+3\right)^3-7x^2-30x-18}{x+3}\)
\(\left(x+3\right)^2-\frac{7x^2+21x+9x+18}{x+3}=\left(x+3\right)^2-\frac{7x.\left(x+3\right)+9.\left(x+3\right)-9}{x+3}\)
\(=\left(x+3\right)^2-\frac{\left(7x+9\right).\left(x+3\right)-9}{x+3}=\left(x+3\right)^2-\left(7x+9\right)-\frac{9}{x+3}\)
=> đa thức dư trong phép chia là 9
p/s: t mới lớp 7_sai sót mong bỏ qua :>
Thực hiện các phép chia:
a,\(\left(x^2-3x-x+3\right):\left(x-3\right)\)
\(b,\left(2x^3-5x^2-4x+3\right):\left(2x-1\right)\)
\(\frac{x^2-3x-x+3}{x-3}=\frac{x\left(x-3\right)-\left(x-3\right)}{x-3}=\frac{\left(x-3\right)\left(x-1\right)}{x-3}=x-1\)( ĐK: \(x\ne3\))
\(\frac{2x^3-5x^2-4x+3}{2x-1}=\frac{\left(2x^3-x^2\right)-\left(4x^2-2x\right)-\left(6x-3\right)}{2x-1}=\frac{x^2\left(2x-1\right)-2x\left(2x-1\right)-3\left(2x-1\right)}{2x-1}=\frac{\left(2x-1\right)\left(x^2-2x-3\right)}{2x-1}=x^2-2x-3\)( ĐK: \(x\ne\frac{1}{2}\))
Tham khảo nhé~
Thực hiện phép tính
\(\left(2x-1\right)\left(3x+2\right)\left(3-x\right)\)
$=(6x^2+x-2)(3-x)$
$=18x^2-6x^3+3x-x^2-6+2x$
$=-6x^3+17x^2+5x-6$
\(\left(\frac{1}{x+1}-\frac{3}{x^3+1}+\frac{3}{x^2-x+1}\right).\frac{3x^2-3x+3}{\left(x+1\right)\left(x+2\right)}-\frac{2x-2}{x^2+2x}\) thực hiện phép tính
\(\left(\frac{1}{x+1}-\frac{3}{x^3+1}+\frac{3}{x^2-x+1}\right)\times\frac{3x^2-3x+3}{\left(x+1\right)\left(x+2\right)}-\frac{2x-2}{x^2+2x}\)
\(=\left[\frac{x^2-x+1}{\left(x+1\right)\left(x^2-x+1\right)}-\frac{3}{\left(x+1\right)\left(x^2-x+1\right)}+\frac{3\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\right]\times\frac{3\left(x^2-x+1\right)}{\left(x+1\right)\left(x+2\right)}-\frac{2\left(x-1\right)}{x\left(x+2\right)}\)
\(=\frac{\left(x^2-x+1\right)-3+3\left(x+1\right)}{\left(x+1\right)\left(x^2-x+1\right)}\times\frac{3\left(x^2-x+1\right)}{\left(x+1\right)\left(x+2\right)}-\frac{2\left(x-1\right)}{x\left(x+2\right)}\)
\(=\frac{x^2-x+1-3+3x+3}{x+1}\times\frac{3}{\left(x+1\right)\left(x+2\right)}-\frac{2\left(x-1\right)}{x\left(x+2\right)}\)
\(=\frac{x^2+2x+1}{x+1}\times\frac{3}{\left(x+1\right)\left(x+2\right)}-\frac{2\left(x-1\right)}{x\left(x+2\right)}\)
\(=\frac{3\left(x+1\right)^2}{\left(x+1\right)\left(x+1\right)\left(x+2\right)}-\frac{2\left(x-1\right)}{x\left(x+2\right)}\)
\(=\frac{3x}{x\left(x+2\right)}-\frac{2x-2}{x\left(x+2\right)}\)
\(=\frac{3x-2x+2}{x\left(x+2\right)}\)
\(=\frac{x+2}{x\left(x+2\right)}\)
\(=\frac{1}{x}\)
Thực hiện phép tính
a/\(\left(2x^2-3x\right)\left(5x^2-2x+1\right)\)
b/\(\left(2x^4-x^3+3x^2\right):\left(\frac{1}{3}x^2\right)\)
a)\(\left(2x^2-3x\right)\left(5x^2-2x+1\right)\)
\(=2x^2\left(5x^2-2x+1\right)-3x\left(5x^2-2x+1\right)\)
\(=10x^4-4x^3+2x^2-15x^3+6x^2-3x\)
\(=10x^4-19x^3+8x^2-3x\)
a. \(\left(2x^2-3x\right)\left(5x^2-2x+1\right)\)
\(=10x^4-4x^3+2x^2-15x^3+6x^2-3x\)
\(=10x^4-19x^3+8x^2-3x\)
b. \(\left(2x^4-x^3+3x^2\right):\left(\frac{1}{3}x^2\right)\)
\(=\left(2x^4-x^3+3x^2\right).\frac{3}{x^2}\)
\(=0,6x^2-3x+0,9\)
Bài 2 . Thực hiện phép tính
a)\(6x^3\)\(\left(\dfrac{1}{3}x^2-\dfrac{5}{2}-\dfrac{1}{6}\right)\)\(-2x^5\)\(-x^3\)
b)\(\left(x-3\right)\left(x^2+3x-2\right)\)
c)\(\left(4x^3-4x^2-5x+4\right):\left(2x+1\right)\)
a: =2x^5-15x^3-x^2-2x^5-x^3=-16x^3-x^2
b: =x^3+3x^2-2x-3x^2-9x+6
=x^3-11x+6
c: \(=\dfrac{4x^3+2x^2-6x^2-3x-2x-1+5}{2x+1}\)
\(=2x^2-3x-1+\dfrac{5}{2x+1}\)
a) \(6x^3\left(\dfrac{1}{3}x^2-\dfrac{5}{2}-\dfrac{1}{6}\right)-2x^5-x^3\)
\(=6x^3\left(\dfrac{1}{3}x^2-\dfrac{16}{6}\right)-2x^5-x^3\)
\(=2x^5-16x^3-2x^5-x^3\)
\(=-17x^3\)
b) \(\left(x+3\right)\left(x^2+3x-2\right)\)
\(=x^3+3x^2-2x+3x^2+9x-6\)
\(=x^3+6x^2+7x-6\)
c) \(\left(4x^3-4x^2-5x+4\right):\left(2x+1\right)\)
\(=2x^2+4x^3-2x-4x^2-\dfrac{5}{2}-5x+\dfrac{2}{x}+4\)
\(=4x^3-2x^2-7x+\dfrac{2}{x}+\dfrac{3}{2}\)
thực hiện phép tính
\(\left(x-1\right)\left(x-3\right)-\left(4-x\right)\left(2x+1\right)-3x^2+2x-5\)
Mọi người ơi, giúp mình với mình đang cần gấp
thank mọi người
1 thực hiện phép nhân
1)\(-3\left(-x+3\right)\)
2)\(-5x^3\left(-3x+5\right)\)
3)\(-2x\left(-2x-6\right)\)
4)\(-3x^3\left(-2x-12\right)\)
5)\(-10x\left(-5x+2\right)\)
6)\(-2x^2\left(-3x^3+4x^2-5\right)\)
7)\(-x^2\left(-2x^3-x+3\right)\)
8)\(-2^3\left(-2-6\right)\)
9)\(\left(-x-3\right)\left(x+2\right)\)
10)\(\left(2x-3\right)\left(5-x\right)\)
11)\(\left(-x+6\right)\left(-x-2\right)\)
12)\(\left(3x-1\right)\left(-3-2x\right)\)
13)\(\left(-5x-3\right)\left(2-x\right)\)
14) \(\left(2x-1\right)\left(4x^2+2x+1\right)\)
15) \(\left(x-3\right)\left(1-2x-5y\right)\)
16)\(\left(x-2\right)\left(x^2+4\right)\left(x+2\right)\)
17)\(\left(-3+1\right)\left(9x^2+1\right)\left(-3x-1\right)\)
18)\(-\left(2x+1\right)\left(2-1\right)\left(x+1\right)\)
19)\(\left(2x^2-3x+5\right)\left(x^2-8x+2\right)\)
20)\(\left(3x^2y-6xy+9x\right)\left(-xy\right)\)
1. -3(-x+3)
= 3x - 6
2. -5x3 (-3x + 5)
= 15x4 - 25x3
3. -2x (-2x - 6)
= 4x2 + 12x