tính:
a)(5x-2)2=64
b)25x+1=64
giúp lẹ
Những câu hỏi liên quan
1/x-5x^2-25x-15/25x^2-1
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(5x-1)^2 + (5x+1)^2-2(25x^2-1)
\(=\left(5x-1\right)^2+\left(5x+1\right)^2-2\left(5x-1\right)\left(5x+1\right)\)
\(=\left(5x-1-5x-1\right)^2\)
\(=\left(-2\right)^2=4\)
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(5x-1)2+(5x+1)2-2(25x2-1)=(5x-1)2+(5x+1)2-2(52x2-12)
=(5x-1)2+(5x+1)2-2[(5x2)-12]
=(5x-1)2+(5x+1)2-2(5x-1)(5x+1)
=(5x-1)2+(5x+1)2-(5x-1)(5x+1)-(5x-1)(5x+1)
=(5x-1)(5x-1-5x+1)+(5x+1)(5x+1-5x-1)
=(5x-1).0+(5x+1).0
=0+0
=0
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(4+10x+25x22) (5x-2)-5(5x-1)(5x+1)
Tính
\(2^3-\left(5x\right)^3-5\times\left(5x\right)^2\)+ 5
\(=8-125x^3-125x^2+5\)
\(=-125x^2\left(x-1\right)+13\)
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5. a) \(\dfrac{4x+13}{5x\left(x-7\right)}-\dfrac{x-48}{5x\left(7-x\right)};\) b) \(\dfrac{1}{x-5x^2}-\dfrac{25x-15}{25x^2-1}\)
a, \(\dfrac{4x+13}{5x\left(x-7\right)}-\dfrac{x-48}{5x\left(7-x\right)}\)
\(=\dfrac{4x+13}{5x\left(x-7\right)}+\dfrac{x-48}{5x\left(x-7\right)}\)
\(=\dfrac{4x+13+x-48}{5x\left(x-7\right)}\)
\(=\dfrac{5x-35}{5x\left(x-7\right)}\)
\(=\dfrac{5\left(x-7\right)}{5x\left(x-7\right)}=\dfrac{1}{x}\)
b, \(\dfrac{1}{x-5x^2}-\dfrac{25x-15}{25x^2-1}\)
\(=\dfrac{1}{x\left(1-5x\right)}+\dfrac{25x-15}{\left(1-5x\right)\left(1+5x\right)}\)
\(=\dfrac{1+5x}{x\left(x-5x\right)\left(1+5x\right)}+\dfrac{x\left(25x-15\right)}{x\left(1-5x\right)\left(1+5x\right)}\)
\(=\dfrac{1+5x+25x^2-15x}{x\left(1-5x\right)\left(1+5x\right)}\)\(=\dfrac{25x^2-10x+1}{x\left(1-5x\right)\left(1+5x\right)}=\dfrac{\left(5x-1\right)^2}{x.\left(1-5x\right)\left(1+5x\right)}\)
\(=\dfrac{\left(5x-1\right)^2}{-x\left(5x-1\right)\left(1+5x\right)}\) \(=\dfrac{-\left(5x-1\right)}{x\left(1+5x\right)}\)
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(5x-1)(5x+1)+4-25x2+6x
\(=25x^2-1+4-25x^2+6x=6x+3=3\left(2x+1\right)\)
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\(=25x^2-1+4-25x^2+6x\)
\(=6x+3\)
\(=3\left(2x+1\right)\)
T nha
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Xem thêm câu trả lời
(3x^2-16x) ÷ (-3x) +x(x-4) =-2 (5x^3+20x^2-25x) ÷25x=(x-1) (x+2) (3x+1) ^3=3x+1 x^2-4x+4=9(x-2) Tìm x
d: ta có: \(x^2-4x+4=9\left(x-2\right)\)
\(\Leftrightarrow\left(x-2\right)\left(x-11\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=11\end{matrix}\right.\)
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thực hiện phép tính
a)\(\dfrac{1}{x-5x^2}\)-\(\dfrac{25x-15}{25x^2-1}\)
b)(-\(\dfrac{1}{x^2-4x}+\dfrac{2}{16-x^2}-\dfrac{-1}{4x+16}\))\(\div\dfrac{1}{4x}\)
`a)1/[x-5x^2]-[25x-15]/[25x^2-1]`
`=[-(5x+1)-x(25x-15)]/[x(5x-1)(5x+1)]`
`=[-5x-1-25x^2+15x]/[x(5x-1)(5x+1)]`
`=[-25x^2+10x-1]/[x(5x-1)(5x+1)]`
`=[-(5x-1)^2]/[x(5x-1)(5x+1)]`
`=[1-5x]/[x(5x+1)]`
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`b)(-1/[x^2-4x]+2/[16-x^2]-[-1]/[4x+16]):1/[4x]`
`=[-4(x+4)-8x+x(x-4)]/[4x(x-4)(x+4)].4x`
`=[-4x-16-8x+x^2-4x]/[(x-4)(x+4)]`
`=[x^2-16x-16]/[x^2-16]`
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kết quả phép chia (25x^5y - 20x^3y^2 - 5x^3y) : 5x^3y là:
A.5x^2y - 4y - x B.5x^2 + 4y C. 5x^2 - 4y D.5x^2 - 4y - 1
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Bài 1:Tính:
a,(5x-y)2
b ( \(\dfrac{1}{4}\)+ y)2
a)\(25x^2-10x+y^2\)
b)\(\dfrac{1}{16}+\dfrac{1}{2}y+y^2\)
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\(\dfrac{4}{-25x^2+20x-3}=\dfrac{3}{5x-1}-\dfrac{2x}{5x-3}\)
Đk: \(x\ne\dfrac{3}{5};x\ne\dfrac{1}{5}\)
Pt \(\Leftrightarrow\dfrac{4}{\left(5x-3\right)\left(1-5x\right)}=\dfrac{-3\left(5x-3\right)}{\left(1-5x\right)\left(5x-3\right)}-\dfrac{2x\left(1-5x\right)}{\left(1-5x\right)\left(5x-3\right)}\)
\(\Rightarrow4=-3\left(5x-3\right)-2x\left(1-5x\right)\)
\(\Leftrightarrow-10x^2+17x-5=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{17+\sqrt{89}}{20}\left(tmpt\right)\\x=\dfrac{17-\sqrt{89}}{20}\left(ktmpt\right)\end{matrix}\right.\)
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