tìm x
a) x3 + 3x = 12.11
b) x04 + 40x = 101.11
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x. ( 4 + 40 ) = 101 . 11
x. 44 = 1111
x = 1111 : 44
x = 25,25
x04 + 40x = 101.11
=> 100x + 4 + 400 + x = 1111
=> 101x + 404 = 1111
=> x = 7
x04+40x = 100xX +4 + 400 +X = 101xX +404 = 101xX +101x4 =101x (X+4) = 101x11 => X+4 =11 => X =7
a/ (x+1)+(x+2)+(x+3)+....+(x+50)=2275
<=> (x+x+...+x)+(1+2+3+...+50)=2275
<=> \(50x+\frac{50\left(50+1\right)}{2}=2275\)
<=> 50.x+1275=2275
<=> 50x=1000
=> x=1000:50 => x=20
b/ x04+40x=101x11
<=> 100x+4+400+x=1111
<=> 101x=707
=> x=707:101 => x=7
a, ( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 50 ) = 2275
x x 50 + ( 50 + 1 ) x ( 50 : 2 ) = 2257
x x 50 + 51 x 25 = 2257
x x 50 + 1275 = 2257
x x 50 = 2257 - 1275
x x 50 = 982
x = 982 : 50
x = 19,64
a) \(\Rightarrow\left(x-1\right)^3=0\Rightarrow x=1\)
b) \(\Rightarrow\left(x^3-1\right)\left(x^3+1\right)=0\Rightarrow\left(x-1\right)\left(x+1\right)\left(x^2-x+1\right)\left(x^2+x+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)(do \(\left\{{}\begin{matrix}x^2-x+1=\left(x-\dfrac{1}{2}\right)^2+\dfrac{3}{4}>0\\x^2+x+1=\left(x+\dfrac{1}{2}\right)^2+\dfrac{3}{4}>0\end{matrix}\right.\))
c) \(\Rightarrow4x\left(x^2-9\right)=0\Rightarrow4x\left(x-3\right)\left(x+3\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=3\\x=-3\end{matrix}\right.\)
d) \(\Rightarrow\left(x-2\right)^3=0\Rightarrow x=2\)
a) \(x^3-3x^2+3x-1=0\Rightarrow\left(x-1\right)^3=0\Rightarrow x-1=0\)
\(\Rightarrow x=1\)
b) \(x^6-1=0\Rightarrow\left(x^3\right)^2-1=0\Rightarrow\left(x^3-1\right)\left(x^3+1\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x^3-1=0\\x^3+1=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=1\\x=-1\end{matrix}\right.\)
c) \(4x^3-36x=0\Rightarrow4x\left(x^2-36\right)=0\Rightarrow4x\left(x-6\right)\left(x+6\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}4x=0\\x-6=0\\x+6=0\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=0\\x=6\\x=-6\end{matrix}\right.\)
d) \(x^3-6x^2+12x-8=0\) (đề bài như vậy mới làm đc, nếu là +8 thì mình xin bó tay nhé)
\(\Rightarrow x^3-3\cdot x^2\cdot2+3\cdot x\cdot2^2-2^3=0\)
\(\Rightarrow\left(x-2\right)^3=0\Rightarrow x-2=0\Rightarrow x=2\)
a: ta có: \(x^2+3x-\left(2x+6\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=2\end{matrix}\right.\)
b: Ta có: \(5x+20-x^2-4x=0\)
\(\Leftrightarrow\left(x+4\right)\left(5-x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-4\\x=5\end{matrix}\right.\)
a: P(x) chia hết cho x-2
=>x^4-2x^3+3x^3-6x^2+12x^2-24x-16x+32+m-2017 chia hết cho x-2
=>m-2017=0
=>m=2017
b: P(x)=x^4+x^3+6x^2-40x+32
P(x)=0
=>x^4-2x^3+3x^3-6x^2+12x^2-24x-16x+32=0
=>(x-2)(x^3+3x^2+12x-16)=0
=>x^3+3x^2+12x-16=0 hoặc x-2=0
=>x^3-x^2+4x^2-4x+16x-16=0 hoặc x-2=0
=>x-1=0 hoặc x=2
=>x=1 hoặc x=2
a, x3 + 3x = 12.11
<=> x . ( 3 + 3 ) = 132
<=> x . 6 = 132
<=> x = 132 : 6
<=> x = 22
b, x04 + 40x = 101.11
<=> x . ( 4 + 40 ) = 1111
<=> x . 44 = 1111
<=> x = 1111 : 44
<=> x = 25,25
a) x3+3x=12.11
3x+3x=132
6x=132
x=132:6
x=22