25+36x[x-x]-25
Những câu hỏi liên quan
x^2-25=..... 16x^2+8x+1=...... 36x^2-36x+9=.......
√36x-72 - 15 √x-2/25 = 4(5+√x-2)
\(\sqrt{36x-72}-15\sqrt{\frac{x-25}{25}}=4\left(5+\sqrt{x-2}\right)\)
\(\sqrt{36x-72}-15\sqrt{\dfrac{x-2}{25}}=4\left(5+\sqrt{x-2}\right)\)
\(\sqrt{36x-72}-15\sqrt{\dfrac{x-2}{25}}=20+4\sqrt{x-2}\)
\(\Leftrightarrow6\sqrt{x-2}-3\sqrt{x-2}-4\sqrt{x-2}=20\)
\(\Leftrightarrow-\sqrt{x-2}=20\)(vô lý)
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\(x\left(8x^2-36x+53\right)=25+\sqrt[3]{3x-5}\)
\(\Leftrightarrow8x^3-36x^2+51x-22+2x-3-\sqrt[3]{3x-5}=0\)
\(\Leftrightarrow8x^3-36x^2+51x-22+\dfrac{8x^3-36x^2+51x-22}{\left(2x-3\right)^2+\left(2x-3\right)\sqrt[3]{3x-5}+\sqrt[3]{\left(3x-5\right)^2}}=0\)
\(\Leftrightarrow\left(8x^3-36x^2+51x-22\right)\left(1+\dfrac{1}{\left(2x-3\right)^2+\left(2x-3\right)\sqrt[3]{3x-5}+\sqrt[3]{\left(3x-5\right)^2}}\right)=0\)
\(\Leftrightarrow8x^3-36x^2+51x-22=0\)
\(\Leftrightarrow\left(x-2\right)\left(8x^2-20x+11\right)=0\)
\(\Leftrightarrow...\)
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Cách khác: (Đưa về hàm đặc trưng)
\(PT\Leftrightarrow8x^3-36x^2+53x-25=\sqrt[3]{3x-5}\)
\(\Leftrightarrow\left(2x-3\right)^3+2x-3=3x-5+\sqrt[3]{3x-5}\). (*)
Xét hàm \(f\left(t\right)=t^3+t\). Ta thấy f(t) đồng biến trên \(\mathbb{R}\).
Do đó \(\left(\cdot\right)\Leftrightarrow2x-3=\sqrt[3]{3x-5}\)
\(\Leftrightarrow8x^3-36x^2+54x-27=3x-5\)
\(\Leftrightarrow8x^3-36x^2+51x-22=0\)
\(\Leftrightarrow\left(x-2\right)\left(8x^2-20x+11\right)=0\Leftrightarrow...\)
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tìm x biết
căn 36x-72+15căn x+2/25=4(5+căn x-2)
tinh hop ly a) (-25)x68+(-34)x(-250) b)(-48)x72+36x(-304) c)136x(-47)+36x47 d) 31x2015+17x2015-35x2015+(-25)x(-2015)+12x2015
Viết mỗi đa thức sau sang dạng tích hoặc luỹ thừa
a, 9x\(^2\)-12x+4 ; b, 25+10x+x\(^2\)
c, 36x\(^2\)-25 ; d, x\(^3\)-3x\(^2\)y+3xy\(^2\)-1
a) \(9x^2-12x+4=\left(3x-2\right)^2\)
b) \(25+10x+x^2=\left(x+5\right)^2\)
c) \(36x^2-25=\left(6x-5\right)\left(6x+5\right)\)
d) \(x^3-3x^2y+3xy^2-y^3=\left(x-y\right)^3\)
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a: \(9x^2-12x+4=\left(3x-2\right)^2\)
b: \(x^2+10x+25=\left(x+5\right)^2\)
c: \(36x^2-25=\left(6x-5\right)\left(6x+5\right)\)
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Tìm x :
( 36x2 - 25 ) - ( 6x + 5 ) ( x + 1) = 0
\(\left(36x^2-25\right)-\left(6x+5\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(6x+5\right)\left(6x-5\right)-\left(6x+5\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(6x+5\right)\left(6x-5-x-1\right)=0\)
\(\Leftrightarrow\left(6x+5\right)\left(5x-6\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-5}{6}\\x=\frac{6}{5}\end{cases}}\)
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\(\left(36x^2-25\right)-\left(6x+5\right)\left(x+1\right)=0\Leftrightarrow\left(6x-5\right)\left(6x+5\right)-\left(6x+5\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(6x+5\right)\left(5x-6\right)=0\Leftrightarrow\orbr{\begin{cases}x=\frac{-5}{6}\\x=\frac{6}{5}\end{cases}}\)
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......
=>(6x+5)(6x-5) - (6x+5)(x+1)=0
=>(6x+5)(5x-4)=0
=>x=-5/6 và x= 4/5
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