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e)(3x-1)(2x+7)-(x+1)(6x-5)=16
=>\(6x^2-2x+21x-7-6x^2-6x+5x+5\)=16
=>18x-2=16
=> 18x=18
=> x=1
a.\(6x^2-\left(2x-3\right)\left(3x+2\right)-1=0\Leftrightarrow6x^2-\left(6x^2-2x-6\right)-1=0\)
\(\Leftrightarrow2x+5=0\Leftrightarrow x=-\frac{5}{2}\)
b. \(\left(x-3\right)\left(x+7\right)-\left(x+5\right)\left(x-1\right)=0\Leftrightarrow x^2+4x-21-\left(x^2+4x-5\right)=0\)
\(\Leftrightarrow-16=0\)
Vậy không có x thỏa mãn.
\(f\left(x\right)=\left(x-1\right).g\left(x\right)\)
\(\Rightarrow3x^3-2x^2+x+5=\left(x-1\right)\left(3x^2+ax+b\right)\)
\(\Rightarrow3x^3-2x^2+x+5=3x^3+ax^2+bx-3x^2-ax-b\)
\(\Rightarrow-2x^2+x+5=x^2\left(a-3\right)+x\left(b-a\right)-b\)
-Bạn kiểm tra lại đề.
* Trả lời:
\(\left(1\right)\) \(-3\left(1-2x\right)-4\left(1+3x\right)=-5x+5\)
\(\Leftrightarrow-3+6x-4-12x=-5x+5\)
\(\Leftrightarrow6x-12x+5x=3+4+5\)
\(\Leftrightarrow x=12\)
\(\left(2\right)\) \(3\left(2x-5\right)-6\left(1-4x\right)=-3x+7\)
\(\Leftrightarrow6x-15-6+24x=-3x+7\)
\(\Leftrightarrow6x+24x+3x=15+6+7\)
\(\Leftrightarrow33x=28\)
\(\Leftrightarrow x=\dfrac{28}{33}\)
\(\left(3\right)\) \(\left(1-3x\right)-2\left(3x-6\right)=-4x-5\)
\(\Leftrightarrow1-3x-6x+12=-4x-5\)
\(\Leftrightarrow-3x-6x+4x=-1-12-5\)
\(\Leftrightarrow-5x=-18\)
\(\Leftrightarrow x=\dfrac{18}{5}\)
\(\left(4\right)\) \(x\left(4x-3\right)-2x\left(2x-1\right)=5x-7\)
\(\Leftrightarrow4x^2-3x-4x^2+2x=5x-7\)
\(\Leftrightarrow-x-5x=-7\)
\(\Leftrightarrow-6x=-7\)
\(\Leftrightarrow x=\dfrac{7}{6}\)
\(\left(5\right)\) \(3x\left(2x-1\right)-6x\left(x+2\right)=-3x+4\)
\(\Leftrightarrow6x^2-3x-6x^2-12x=-3x+4\)
\(\Leftrightarrow-15x+3x=4\)
\(\Leftrightarrow-12x=4\)
\(\Leftrightarrow x=-\dfrac{1}{3}\)
Noob ơi, bạn phải đưa vào máy tính ý solve cái là ra x luôn, chỉ tội là đợi hơi lâu
a, 4.(18 - 5x) - 12(3x - 7) = 15(2x - 16) - 6(x + 14)
=> 72 - 20x - 36x + 84 = 30x - 240 - 6x - 84
=> (72 + 84) + (-20x - 36x) = (30x - 6x) + (-240 - 84)
=> 156 - 56x = 24x - 324
=> 24x + 56x = 324 + 156
=> 80x = 480
=> x = 480 : 80 = 6
Vậy x = 6
1 ) 3x^2 - 11x + 6 = 3x^2 - 9x - 2x + 6 = 3x( x- 3 ) - 2( x - 3) = ( 3x - 2 )( x - 3 )
2) 8x^2 - 2x - 1 = 8x^2 - 4x + 2x - 1 = 4x( 2x - 1 ) + 2x - 1 = ( 4x + 1 )( 2x - 1 )
3; 8x^2 - 2x - 1 =8x^2 - 4x + 2x - 1 = 4x( 2x - 1 ) + 2x - 1 = ( 4x + 1 )( 2x - 1 )
4; x^4 - 3x^2 - 4 = x^4 - 4x^2 + x^2 - 4 = x^2 ( x ^2 - 4 ) + x^2 - 4 = ( x^2 + 1 )( x^2 - 4 ) = ( x^2 + 1 )( x - 2 )( x + 2)
5) = x^2 ( x + 2 ) - 3 ( x+ 2 ) = ( x^2 - 3 )( x + 2 )
Nhiều quá
\(\left|3x-2018\right|+\left|x-2017\right|=\left|2x-1\right|\)
\(\Rightarrow\orbr{\begin{cases}3x-2018+x-2017=2x-1\\-\left(3x-2018\right)+\left[-\left(x-2017\right)\right]=2x-1\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}4x-4035=2x-1\\\left(-3x-x\right)+\left(2018+2017\right)=2x-1\end{cases}}\)
Làm tiếp
TH2:
\(\left|3x-2018\right|+\left|x-2017\right|=\left|2x-1\right|\)
\(\Rightarrow\orbr{\begin{cases}3x-2018+x-2017=-2x+1\\-\left(3x-2018\right)+\left[-\left(x-2017\right)\right]=-2x+1\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}4x-4035=-2x+1\\\left(-3x-x\right)+\left(2018+2017\right)=-2x+1\end{cases}}\)
Tự tiếp tiếp nha bạn
Bài sau cũng tg tự vậy mà làm
c)3(2x-1)-5(x-3)+6(3x-4)=24
<=>6x-3-5x-15+18x-24=24
<=>19x-12=24
<=>19x=36
<=>x=\(\frac{36}{19}\)
d)2x(5-3x)+2x(3x-5)-3(x-7)=3
<=>10x-6x2+6x2-10x-3x-21=3
<=>-3(x-7)=3
<=>21-3x=3
<=>-3x=-18
<=>x=6