Thựcc hiện phép tính
\(2x^4-5x^3+4x^2\left(\frac{-1}{2}x^2+\frac{5}{4}x+1\right)\)
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Thực hiện phép tính
a) \(\left(\frac{2x+1}{2x-2}+\frac{3}{x^2-1}-\frac{x+3}{2x+2}\right).\frac{4x^2-4}{3}\)
b) \(\left(\frac{5x+2}{x^2-10x}+\frac{5x-2}{x^2+10x}\right).\frac{x^2-100}{x^2+4}\)
c) \(\frac{1}{x-1}-\frac{x^3-x}{x^2+1}.\left(\frac{1}{x^2-2x+1}+\frac{1}{1-x^2}\right)\)
Cho \(x=\frac{1}{2}\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\)
Tính \(A=\left(4x^5+4x^4-x^3+1\right)^{19}+\left(\sqrt{x^5+4x^4-5x^3+5x+3}\right)^3+\left(\frac{1-\sqrt{2x}}{\sqrt{2x^2+2x}}\right)\)
Ta có:
x = \(\frac{1}{2}\)\(\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\)
= \(\frac{1}{2}\)\(\sqrt{\frac{\left(\sqrt{2}-1\right)^2}{1}}\)
= \(\frac{1}{2}\)(\(\sqrt{2}\)-1)
=> 2x = \(\sqrt{2}\)-1
=> (2x)2= ( \(\sqrt{2}\)-1)2
=> 4x2= 2-2\(\sqrt{2}\)+1
=> 4x2= -2( \(\sqrt{2}\)-1)+1
=> 4x2= -4x +1 => 4x2+4x-1=0
Lại có:
A1= (\(4x^5\)+\(4x^4\)- \(x^3\)+1)19
= [ x3( 4x2+4x-1) +1]19
=1
A2=( \(\sqrt{4x^5+4x^4-5x^3+5x+3}\))3
= (\(\sqrt{x^3\left(4x^2+4x-1\right)-x\left(4x^2+4x-1\right)+\left(4x^2+4x-1\right)+4}\))3
= 23=8
A3= \(\frac{1-\sqrt{2x}}{\sqrt{2x^2+2x}}\)
= \(\sqrt{2}\)- \(\sqrt{2}\)\(\sqrt{1-\sqrt{2}}\)
Cộng 3 số vào ta được A
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Xem thêm câu trả lời
Thực hiện phép tính:
\(a.\left(x+1\right)\left(2x-3\right)+\left(x+2\right)^2-3x^2-3x\)
\(b.\left(x^2+2x-3\right):\left(x+1\right)+x^2-3x-2\)
\(c.\frac{1}{xy-x^2}-\frac{1}{y^2-xy}\)
\(d.\frac{x-1}{x^2-5x+4}-\frac{4}{x^2-4x}\)
1)2x(25x-4)-(5x-2)(5x+1)8 / 5)2left(x-2right)-3left(3x-1right)left(x-3right)
2)x(4x-3)-(2x-2)(2x-1)5 / 6)frac{2}{x+1}-frac{1}{x-2}frac{3x-11}{left(x+1right)left(x-2right)}
3)frac{5}{2x+3}+frac{3}{9-x^2}frac{8}{7left(x3right)} / 7)frac{5x-2}{6}+frac{3-4x}{2}2-frac{x+7}{3}
4)frac{2}{3left(x-2right)}+frac{5}{12-3x^2}frac{3}{4left(x+2right)} /...
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1)2x(25x-4)-(5x-2)(5x+1)=8 / 5)\(2\left(x-2\right)-3\left(3x-1\right)=\left(x-3\right)\)
2)x(4x-3)-(2x-2)(2x-1)=5 / 6)\(\frac{2}{x+1}-\frac{1}{x-2}=\frac{3x-11}{\left(x+1\right)\left(x-2\right)}\)
3)\(\frac{5}{2x+3}+\frac{3}{9-x^2}=\frac{8}{7\left(x=3\right)}\) / 7)\(\frac{5x-2}{6}+\frac{3-4x}{2}=2-\frac{x+7}{3}\)
4)\(\frac{2}{3\left(x-2\right)}+\frac{5}{12-3x^2}=\frac{3}{4\left(x+2\right)}\) / 8)\(\frac{2}{x+1}-\frac{1}{x-2}=\frac{3x-11}{\left(x+1\right)\left(x-2\right)}\)
Đây là lớp 8 nha các b giúp mk với
Do mk viết nhầm
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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: \(=\dfrac{4x^3+2x^2-6x^2-3x-2x-1+5}{2x+1}\)
\(=2x^2-3x-1+\dfrac{5}{2x+1}\)
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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) \(\left(4x^3-4x^2-5x+4\right):\left(2x+1\right)\)
\(=2x^2+4x^3-2x-4x^2-\dfrac{5}{2}-5x+\dfrac{2}{x}+4\)
\(=4x^3-2x^2-7x+\dfrac{2}{x}+\dfrac{3}{2}\)
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Cho \(x=\frac{1}{2}\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\) Tính giá trị BT
\(A=\left(4x^5+4x^4-x^3+1\right)^{2018}+\left(\sqrt{4x^5+4x^4-5x^3+3}\right)^3+\left(\frac{1-\sqrt{2}x}{\sqrt{2x^2+2x}}\right)\)tại giá trị x
Cho x = \(\frac{1}{2}\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\). Tính giá trị biểu thức:
\(A=\left(4x^5+4x^4-x^3+1\right)^{2018}+\left(\sqrt{4x^5+4x^4-5x^3+3}\right)^3+\left(\frac{1-2\sqrt{x}}{\sqrt{2x^2}+2x}\right)^{2017}\) tại giá trị x đã cho
Cho \(x=\frac{1}{2}\sqrt{\frac{\sqrt{2}-1}{\sqrt{2}+1}}\).
Tính giá trị phương trình: \(A=\left(4x^5+4x^4-x^3+1\right)^{2018}+\left(\sqrt{4x^5+4x^4-5x^3+3}\right)^3+\left(\frac{1-\sqrt{2}x}{\sqrt{2x^2+2x}}\right)^{2017}\)
tại giá trị của x.
giải các hệ BPT sau:
a) left{{}begin{matrix}5x-24x+55x-4 x+2end{matrix}right.
b) left{{}begin{matrix}2x+13x+45x+3ge8x-9end{matrix}right.
c) left{{}begin{matrix}frac{5x+2}{3}ge4-xfrac{6-5x}{13} 3x+1end{matrix}right.
d) left{{}begin{matrix}frac{4x-5}{7} x+3frac{3x+8}{4}2x-5end{matrix}right.
e) left{{}begin{matrix}6x+frac{5}{7} 4x+7frac{8x+3}{2} 2x+5end{matrix}right.
f) left{{}begin{matrix}15x-22x+frac{1}{3}2left(x-4right) frac{3x-14}{2}end{matrix}right.
g) left{{}begin{matrix}x-1le2x-33x x+...
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giải các hệ BPT sau:
a) \(\left\{{}\begin{matrix}5x-2>4x+5\\5x-4< x+2\end{matrix}\right.\)
b) \(\left\{{}\begin{matrix}2x+1>3x+4\\5x+3\ge8x-9\end{matrix}\right.\)
c) \(\left\{{}\begin{matrix}\frac{5x+2}{3}\ge4-x\\\frac{6-5x}{13}< 3x+1\end{matrix}\right.\)
d) \(\left\{{}\begin{matrix}\frac{4x-5}{7}< x+3\\\frac{3x+8}{4}>2x-5\end{matrix}\right.\)
e) \(\left\{{}\begin{matrix}6x+\frac{5}{7}< 4x+7\\\frac{8x+3}{2}< 2x+5\end{matrix}\right.\)
f) \(\left\{{}\begin{matrix}15x-2>2x+\frac{1}{3}\\2\left(x-4\right)< \frac{3x-14}{2}\end{matrix}\right.\)
g) \(\left\{{}\begin{matrix}x-1\le2x-3\\3x< x+5\\5-3x\le2x-6\end{matrix}\right.\)
h) \(\left\{{}\begin{matrix}2x+\frac{3}{5}>\frac{3\left(2x-7\right)}{3}\\x-\frac{1}{2}< \frac{5\left(3x-1\right)}{2}\end{matrix}\right.\)
j) \(\left\{{}\begin{matrix}\frac{3x+1}{2}-\frac{3-x}{3}\le\frac{x+1}{4}-\frac{2x-1}{3}\\3-\frac{2x+1}{5}>x+\frac{4}{3}\end{matrix}\right.\)
https://i.imgur.com/NOxfqjV.jpg
https://i.imgur.com/awOKwJi.jpg
https://i.imgur.com/a0ApmAE.jpg