(13x+1)2=169
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a, 13.(x-9)=169
x-9 =169:13
x-9 =13
b, 230+[16+(x,-5)]=315.2\(^3\)
230+[16+(x,-5)]=2520
16+(x,-5)=2520-230
16+(x-5)=2290
x-5 =2290-16
x-5 =2274
x =2274+5
x =2279
c, 13x-3\(^2\)x=2003\(^1\)+1\(^{2016}\)
13x-9x=2004
(13-9)x=2004
4 . x=2004
x=2004:4
x=501
Bài 1
A= x2 + 13x - 30 = x2 + 15x - 2x - 30 = ( x2 +15x) - ( 2x+30) = x(x+15) - 2(x+15) = (x+15)(x-2)
B = -x2+3x-2 = -(x2 - 3x +2 )= -( x2 - x - 2x +2) = - [(x2 - x) - ( 2x - 2)] = - [x(x - 1) - 2(x - 1)] = (x - 1)(x - 2)
Bài 2
a) 4x2 - 169 = (2x)2 - 132 = ( 2x - 13)(2x + 13)
b) 121x3 - 27 đề sai hay sao ý
c) (x + 10)3 = x3 + 30x2 + 300x + 100
d) x3 + y3 = (x + y)(x2 - xy - y2)
k cho mình nhé bạn. Thanks you ! ^^
\(x^2+13x-30\)
\(=x^2+2x-15x-30\)
\(=x\left(x+2\right)-15\left(x+2\right)\)
\(=\left(x+2\right)\left(x-15\right)\)
Bn vt thiếu đề nhé, đề đúng phải như này :)
(169 - 1).(169 - 22).(169 - 32)...(169 - 122).(169 - 132)
= (169 - 1).(169 - 22).(169 - 32)...(169 - 122).(169 - 169)
= (169 - 1).(169 - 22).(169 - 32)...(169 - 122).0
= 0
Tính giá trị biểu thức:
A = (169 - 1 . 1) . (169 - 2 . 2) . ... . (169 - 23 . 23)????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????/
a) \(x^2-3x^3+4x^2-3x+1=0\)
\(\Leftrightarrow-3x^3+5x^2-3x+1=0\)
\(\Leftrightarrow-3x^3+2x^2-x+3x^2-2x+1=0\)
\(\Leftrightarrow x\left(-3x^2+2x-1\right)-1\left(-3x^2+2x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(-3x^2+2x-1\right)=0\)
\(\Rightarrow x-1=0\) \(\Leftrightarrow x=1\)
Vậy \(x=1\)
b) \(3x^4-13x^3+16x^2-13x+3=0\)
\(\Leftrightarrow3x^4-4x^3+4x^2-x-9x^3+12x^2+12x+3=0\)
\(\Leftrightarrow x\left(3x^3-4x^2+4x-1\right)-3\left(3x^3-4x^2+4x-1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(3x^3-4x^2+4x-1\right)=0\)
\(\Leftrightarrow3\left(x-3\right)\left(x-\dfrac{1}{3}\right)\left(x^2-x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{1}{3}\end{matrix}\right.\)
Vậy \(x\in\left\{3;\dfrac{1}{3}\right\}\)
a) Ta có: \(x^2-3x^3+4x^2-3x+1=0\)
\(\Leftrightarrow-3x^3+5x^2-3x+1=0\)
\(\Leftrightarrow-3x^3+3x^2+2x^2-2x-x+1=0\)
\(\Leftrightarrow-3x^2\left(x-1\right)+2x\left(x-1\right)-\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(-3x^2+2x-1\right)=0\)
mà \(-3x^2+2x-1\ne0\forall x\)
nên x-1=0
hay x=1
Vậy: S={1}
b) Ta có: \(3x^4-13x^3+16x^2-13x+3=0\)
\(\Leftrightarrow3x^4-9x^3-4x^3+12x^2+4x^2-12x-x+3=0\)
\(\Leftrightarrow3x^3\left(x-3\right)-4x^2\left(x-3\right)+4x\left(x-3\right)-\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(3x^3-4x^2+4x-1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(3x^3-x^2-3x^2+x+3x-1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left[x^2\left(3x-1\right)-x\left(3x-1\right)+\left(3x-1\right)\right]=0\)
\(\Leftrightarrow\left(x-3\right)\left(3x-1\right)\left(x^2-x+1\right)=0\)
mà \(x^2-x+1\ne0\forall x\)
nên \(\left(x-3\right)\left(3x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\3x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\3x=1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x=\dfrac{1}{3}\end{matrix}\right.\)
Vậy: \(S=\left\{\dfrac{1}{3};3\right\}\)
\(\left(13^{x+1}\right)^{^2}=169=13^2\Rightarrow x+1=1\Rightarrow x=0.\\\)
x=0 nha k mk nha