tìm x
x mũ 2- 4x+4=9[x-2]
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1, \(x^3+4x^2+4x=0\Leftrightarrow x\left(x^2+4x+4\right)=0\)
\(\Leftrightarrow x\left(x+2\right)^2=0\Leftrightarrow x=-2;x=0\)
2, \(\left(x+3\right)^2-4=0\Leftrightarrow\left(x+3-2\right)\left(x+3+2\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+5\right)=0\Leftrightarrow x=-5;x=1\)
3, \(x^4-9x^2=0\Leftrightarrow x^2\left(x^2-9\right)=0\)
\(\Leftrightarrow x^2\left(x-3\right)\left(x+3\right)=0\Leftrightarrow x=0;\pm3\)
4, \(x^2-6x+9=81\Leftrightarrow\left(x-3\right)^2=9^2\)
\(\Leftrightarrow\left(x-3-9\right)\left(x-3+9\right)=0\Leftrightarrow\left(x-12\right)\left(x+6\right)=0\Leftrightarrow x=-6;x=12\)
5, em xem lại đề nhé
à lag tý @@
5, \(x^3+6x^2+9x-4x=0\Leftrightarrow x^3+6x^2+5x=0\)
\(\Leftrightarrow x\left(x^2+6x+5\right)=0\Leftrightarrow x\left(x^2+x+5x+5\right)=0\)
\(\Leftrightarrow x\left(x+1\right)\left(x+5\right)=0\Leftrightarrow x=-5;x=-1;x=0\)
Bài 1:
a: x/-2=-18/x
=>x2=36
=>x=6 hoặc x=-6
b: x/2+x/5=17/10
=>7/10x=17/10
hay x=17/7
a) \(x=\dfrac{25}{72}\)
b)\(x=-\dfrac{1}{4}\)
\(x=\dfrac{3}{2}\)
c)\(x=\dfrac{5}{4}\) hoặc
x \(=\dfrac{8}{5}\)
d và e chịu vì mk kg giỏi lắm về mũ
f)\(x=-2\)
G)\(x=-\dfrac{5}{12}\)
a) \(x^2-\frac{1}{49}=0\)
<=> \(\left(x-\frac{1}{7}\right)\left(x+\frac{1}{7}\right)=0\)
<=> \(\orbr{\begin{cases}x-\frac{1}{7}=0\\x+\frac{1}{7}=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{7}\\x=-\frac{1}{7}\end{cases}}\)
Vậy x = \(\pm\frac{1}{7}\)
b) \(64-\frac{1}{4}x^2=0\)
<=> \(\left(8-\frac{1}{2}x\right)\left(8+\frac{1}{2}x\right)=0\)
<=> \(\orbr{\begin{cases}8-\frac{1}{2}x=0\\8+\frac{1}{2}x=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=16\\x=-16\end{cases}}\)
Vậy \(x=\pm16\)
c) 9x2 + 12x + 4 = 0
<=> (3x + 2)2 = 0
<=> 3x + 2 = 0
<=> x = -2/3
Vậy x = -2/3
e) \(x^2+\frac{1}{4}=x\)
<=> \(x^2-x+\frac{1}{4}=0\)
<=> \(\left(x-\frac{1}{2}\right)^2=0\)
<=> \(x=\frac{1}{2}\)
Vậy \(x=\frac{1}{2}\)
d, sửa đề : \(x^2+4=4x\Leftrightarrow x^2-4x+4=0\Leftrightarrow\left(x-2\right)^2=0\Leftrightarrow x=2\)
i, \(4-\frac{12}{x}+\frac{9}{x^2}=0\)ĐK : \(x\ne0\)
Vì \(x\ne0\)Nhân 2 vế với \(x^2\)phương trình có dạng
\(4x^2-12x+9=0\Leftrightarrow\left(2x-3\right)^2=0\Leftrightarrow x=\frac{3}{2}\)
\(x-4=26\\ \Leftrightarrow x=30\)
\(\left(40+x\right).2=180\\ \Leftrightarrow40+x=90\\ \Leftrightarrow x=50\)
\(\left(14+5x\right):2=3^5:3^2\\ \Leftrightarrow\left(14+5x\right):2=27\\ \Leftrightarrow14+5x=54\\ \Leftrightarrow5x=40\\ \Leftrightarrow x=8\)
a) \(\left(2x-5\right)^2-\left(2x+3\right)\left(2x-3\right)=10\Leftrightarrow\left(4x^2-20x+25\right)-\left(4x^2-9\right)-10=0\)
\(\Leftrightarrow-20x+24=0\Leftrightarrow x=\frac{6}{5}\)
b) \(\left(4x-1\right)\left(x+2\right)-\left(2x+3\right)^2-5\left(x-1\right)=9\Leftrightarrow-10x-15=0\)
\(\Leftrightarrow x=\frac{-3}{2}\)
c) \(\left(x+1\right)^3-\left(x-1\right)^3-2=6\Leftrightarrow\left(x^3+3x^2+3x+1\right)-\left(x^3-3x^2+3x-1\right)-8=0\)
\(\Leftrightarrow6x^2-6=0\Leftrightarrow x=\pm1\)
d) \(\left(x+2\right)\left(x^2-2x+4\right)-\left(x+1\right)\left(x^2-x+1\right)-3\left(-x-2\right)=5\)
\(\Leftrightarrow\left(x^3+8\right)-\left(x^3+1\right)+3x+6=5\Leftrightarrow3x+8=0\Leftrightarrow x=\frac{-8}{3}\)
\(x^2-4x+4=9\left(x-2\right)\)
\(\Leftrightarrow\left(x-2\right)^2=9\left(x-2\right)\)
\(\Leftrightarrow\left(x-2\right)^2-9\left(x-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(x-2\right)\left(x-2-9\right)=0\\\left(x-2\right)\left(x-11\right)=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=0\\x-11=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=11\end{cases}}\)
bác nào giúp em đi em k