Rut gon bt
\(\left(\frac{2+x}{2-x}-\frac{4x^2}{x^2-4}-\frac{2-x}{2+x}\right):\left(\frac{x^2-3x}{2x^2-x^3}\right)\)
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Rut gon bt
\(A=\left(\frac{2+x}{2-x}-\frac{4x^2}{x^2-4}-\frac{2-x}{2+x}\right):\left(\frac{x^2-3x}{2x^2-x^3}\right)\)
Rut gon
\(\frac{1}{2}x^2.\left(6x-3\right)-x.\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)
\(2x\left(3x^3-x\right)-4x^2\left(x-x^2+1\right)+\left(x-3x^2\right)x\)
\(\frac{1}{2}x^2\left(6x-3\right)-x\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)
\(=\frac{1}{2}x^2.6x+\frac{1}{2}x^2.\left(-3\right)+\left(-x\right).x^2+\left(-x\right).\frac{1}{2}+\frac{1}{2}.x+\frac{1}{2}.4\)
\(=3x^3-\frac{3}{2}x^2-x^3-\frac{1}{2}x+\frac{1}{2}x+2\)
\(=\left(3x^3-x^3\right)-\frac{3}{2}x^2+\left(-\frac{1}{2}x+\frac{1}{2}x\right)+2\)
\(=2x^3-\frac{3}{2}x^2+2\)
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\(a,\)\(\frac{1}{2}x^2\left(6x-3\right)-x\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)
\(=3x^3-\frac{3}{2}x^2-x^3-\frac{1}{2}x+\frac{1}{2}x+2\)
\(=2x^3-\frac{3}{2}x^2+2\)
\(b,\)\(2x\left(3x^3-x\right)-4x^2\left(x-x^2+1\right)+\left(x-3x^2\right)x\)
\(=6x^4-2x^2-4x^3+4x^4-4x^2+x^2-3x^3\)
\(=10x^4-7x^3-5x^2\)
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\(\frac{1}{2}x^2.\left(6x-3\right)-x\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)
\(=3x^3-\frac{3}{2}x^2-x^3-\frac{1}{2}x+\frac{1}{2}x+2\)
\(=2x^3-\frac{3}{2}x^2+2\)
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Xem thêm câu trả lời
cho bieu thuc:
\(A=\left(\frac{2+x}{2-x}-\frac{4x^2}{x^2-4}-\frac{2-x}{2+x}\right):\left(\frac{x^2-3x}{2x^2-x^3}\right)\)
a. Tim DKXD roi rut gon A
b. Tim x de A>0
c. Tinh gia tri cua A khi \(\left|x-7\right|=4\)
CHO E=\(\left(\frac{x^3}{x^3-4x}+\frac{6}{6-3x}+\frac{1}{2+x}\right):\left(x+2+\frac{10-x^2}{x-2}\right)\)
a) Rut gon E
b) Tim x thuoc Z sao cho E thuoc Z
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)} /...
Đọc tiếp
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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cho biểu thức A left(frac{3}{4}+frac{3}{x^2+3x}right)chialeft(frac{x^2}{27-3x}+frac{1}{x+3}right)a, rut gon A b, tim x de a-1c, tim cac gia tri nguyen cua x de A co gia tri nguyencho bthuc B left(frac{x^2}{x^3-4x}+frac{6}{6-3x}+frac{1}{x-2}right)chialeft(x-2+frac{16-x^2}{x+2}right)rut gon B tính b khi /x/ 1/2tim x de b2tim x in z de b in z
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cho biểu thức A= \(\left(\frac{3}{4}+\frac{3}{x^2+3x}\right)chia\left(\frac{x^2}{27-3x}+\frac{1}{x+3}\right)\)
a, rut gon A
b, tim x de a<-1
c, tim cac gia tri nguyen cua x de A co gia tri nguyen
cho bthuc B = \(\left(\frac{x^2}{x^3-4x}+\frac{6}{6-3x}+\frac{1}{x-2}\right)chia\left(x-2+\frac{16-x^2}{x+2}\right)\)rut gon B tính b khi /x/ = 1/2tim x de b=2tim x \(\in\) z de b \(\in\) z
Bài 2:
a: \(B=\left(\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{6}{3\left(x-2\right)}+\dfrac{1}{x-2}\right):\left(\dfrac{x^2-4+16-x^2}{x+2}\right)\)
\(=\left(\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{2}{x-2}+\dfrac{1}{x-2}\right):\dfrac{12}{x+2}\)
\(=\left(\dfrac{x}{\left(x-2\right)\left(x+2\right)}-\dfrac{1}{x-2}\right):\dfrac{12}{x+2}\)
\(=\dfrac{x-x-2}{\left(x-2\right)\left(x+2\right)}\cdot\dfrac{x+2}{12}=\dfrac{-1}{6\left(x-2\right)}\)
b: Thay x=1/2 vào B, ta được:
\(B=\dfrac{-1}{6\cdot\left(\dfrac{1}{2}-2\right)}=\dfrac{-1}{6\cdot\dfrac{-3}{2}}=\dfrac{1}{9}\)
Thay x=-1/2 vào B, ta được:
\(B=\dfrac{-1}{6\cdot\left(-\dfrac{1}{2}-2\right)}=-\dfrac{1}{15}\)
c: Để B=2 thì \(\dfrac{-1}{6\left(x-2\right)}=2\)
=>6(x-2)=-1/2
=>x-2=-1/12
hay x=23/12
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1. a, tính gt nhỏ nhất của biểu thức
Afrac{2x^2-16x+41}{x^2-8x+22}
b, tính gt lớn nhất của biểu thúc
Bfrac{3x^2+9x+17}{3x^2+9x+7}
2. cho bt Qleft[left(x^4-x+frac{x-3}{x^3+1}right).frac{left(x^3-2x^2+2x-1right)left(x+1right)}{x^9+x^7-3x^2-3}+1-frac{2left(x+6right)}{x^2+1}right].frac{4x^2+4x+1}{left(x+3right)left(4-xright)}
Đọc tiếp
1. a, tính gt nhỏ nhất của biểu thức
A=\(\frac{2x^2-16x+41}{x^2-8x+22}\)
b, tính gt lớn nhất của biểu thúc
B=\(\frac{3x^2+9x+17}{3x^2+9x+7}\)
2. cho bt Q=\(\left[\left(x^4-x+\frac{x-3}{x^3+1}\right).\frac{\left(x^3-2x^2+2x-1\right)\left(x+1\right)}{x^9+x^7-3x^2-3}+1-\frac{2\left(x+6\right)}{x^2+1}\right].\frac{4x^2+4x+1}{\left(x+3\right)\left(4-x\right)}\)
1.\(A=\frac{2x^2-16x+41}{x^2-8x+22}\) \(=\frac{2\left(x^2-8x+22\right)-3}{x^2-8x+22}=2-\frac{3}{\left(x-4\right)^2+6}\ge\frac{1}{2}\)
Dấu '' = '' xảy ra khi x = 4.
Vậy MinA= \(\frac{1}{2}\) tại x = 4.
b. Câu hỏi của bảo ngọc - Toán lớp 8 | Học trực tuyến
2.a, tìm đk của x để Q đc xđ
b, rút gọn Q
c, chứng minh rằng với các gt của mà gt của bt xđthì -5≤P≤0
Giải các phương trình sau :
a) x^4-left(x^2+2right)4
b) frac{x+2}{x-2}-frac{1}{x}frac{2}{xleft(x-2right)}
c) frac{2x-10}{4}5+frac{2-3x}{6}
d) frac{2x}{left(x-3right)left(x+1right)}+frac{x}{2left(x-3right)}frac{x}{2x+2}
e) left(frac{x+2}{x}right)^2+left(frac{x}{x+2}right)^22
f) left(x-aright)left(x+aright)+2x+a^2-1
g) frac{x-a}{2a}+frac{x-2a}{3a}+frac{x-3a}{4a}+frac{x-4a}{5a}-4
h) left(x^2-3x+4right)^2left(x^2-2x+3right)left(x^2-4x+5right)
i) frac{x^2-4x+12}{x^2-4x+6}x^2-4x+8
Đọc tiếp
Giải các phương trình sau :
a) \(x^4-\left(x^2+2\right)=4\)
b) \(\frac{x+2}{x-2}-\frac{1}{x}=\frac{2}{x\left(x-2\right)}\)
c) \(\frac{2x-10}{4}=5+\frac{2-3x}{6}\)
d) \(\frac{2x}{\left(x-3\right)\left(x+1\right)}+\frac{x}{2\left(x-3\right)}=\frac{x}{2x+2}\)
e) \(\left(\frac{x+2}{x}\right)^2+\left(\frac{x}{x+2}\right)^2=2\)
f) \(\left(x-a\right)\left(x+a\right)+2x+a^2=-1\)
g) \(\frac{x-a}{2a}+\frac{x-2a}{3a}+\frac{x-3a}{4a}+\frac{x-4a}{5a}=-4\)
h) \(\left(x^2-3x+4\right)^2=\left(x^2-2x+3\right)\left(x^2-4x+5\right)\)
i) \(\frac{x^2-4x+12}{x^2-4x+6}=x^2-4x+8\)
a,frac{3}{x}+frac{1}{x+3}+frac{3}{x+6}+frac{1}{x+7}frac{1}{1-x}b, frac{1}{x-5}+frac{1}{x-2}+frac{1}{x-1}+frac{1}{x}+frac{1}{x+3}frac{3x-3}{4}c,frac{1}{x-3}+frac{1}{3x+1}+frac{10x-13}{4x-6}frac{1}{x+1}+frac{1}{2x-1}+frac{1}{3x+7}d,frac{x^2+x+1}{2x-1}left(frac{3x^2-x+5}{4x-2}-3right)8e,frac{2x^2-3}{3x-1}left(2x-frac{7+4x}{3x-1}right)2f,frac{xleft(3x-1right)left(3x^2+1right)left(6x^2-3x-1right)}{left(x+1right)^3}frac{1}{2}g, xleft(x^2+2right)left(x^2+2x+8+frac{12}{x-2}right)3left(x-2right)
Đọc tiếp
a,\(\frac{3}{x}+\frac{1}{x+3}+\frac{3}{x+6}+\frac{1}{x+7}=\frac{1}{1-x}\)
b, \(\frac{1}{x-5}+\frac{1}{x-2}+\frac{1}{x-1}+\frac{1}{x}+\frac{1}{x+3}=\frac{3x-3}{4}\)
c,\(\frac{1}{x-3}+\frac{1}{3x+1}+\frac{10x-13}{4x-6}=\frac{1}{x+1}+\frac{1}{2x-1}+\frac{1}{3x+7}\)
d,\(\frac{x^2+x+1}{2x-1}\left(\frac{3x^2-x+5}{4x-2}-3\right)=8\)
e,\(\frac{2x^2-3}{3x-1}\left(2x-\frac{7+4x}{3x-1}\right)=2\)
f,\(\frac{x\left(3x-1\right)\left(3x^2+1\right)\left(6x^2-3x-1\right)}{\left(x+1\right)^3}=\frac{1}{2}\)
g, \(x\left(x^2+2\right)\left(x^2+2x+8+\frac{12}{x-2}\right)=3\left(x-2\right)\)