Tìm x biết:
\(\left|x^2+\left|6x-2\right|\right|=x^2+4\)
Bài 3: Tìm x biết:
1, \(4x^2-36=0\)
2, \(\left(x-1\right)^2+x\left(4-x\right)=11\)
3, \(\left(x-5\right)^2-x.\left(x+2\right)=5\)
4, \(x\left(x+4\right)-x^2-6x=10\)
1: Ta có: \(4x^2-36=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-3\end{matrix}\right.\)
2: Ta có: \(\left(x-1\right)^2+x\left(4-x\right)=11\)
\(\Leftrightarrow x^2-2x+1+4x-x^2=11\)
\(\Leftrightarrow2x=10\)
hay x=5
Tìm x biết
\(\left|x^2+\left|6x-2\right|\right|=x^2+4\)
Không biết mình làm như thế này đúng hay không, các bạn cho ý kiến nhé
\(\left|x^2+\left|6x-2\right|\right|=x^2+4\)
vì \(\left|6x-2\right|\ge0\) và \(x^2\ge0\)nên \(\left|x^2+\left|6x-2\right|\right|=x^2+\left|6x-2\right|\)
Vậy \(x^2+\left|6x-2\right|=x^2+4\)
\(\Leftrightarrow\left|6x-2\right|=4\)
\(\Leftrightarrow\orbr{\begin{cases}6x-2=4\\6x-2=-4\end{cases}\Leftrightarrow\orbr{\begin{cases}x=1\\x=\frac{-1}{3}\end{cases}}}\)
Tìm x, biết :
a) \(\dfrac{2}{3}x\left(x^2-4\right)=0\)
b) \(\left(x+2\right)^2-\left(x-2\right)\left(x+2\right)=0\)
c) \(\left(x^2-y^2+6x+9\right):\left(x+y+3\right)\)
TÌM X, BIẾT
\(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
\(\Leftrightarrow6x^2+4x+27x+18-6x^2-12x-x-2=x^2-x-6x-6\)
\(\Leftrightarrow18x+16=x^2-7x-6\)
\(\Leftrightarrow x^2-7x-18x=16+6\)
\(\Leftrightarrow x^2-15x=22\)
\(\Leftrightarrow x^2-15x-22=0\)
......
Tìm x biết:
\(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x-1\right)-\left(x-6\right)\)
\(\Leftrightarrow\left(6x^2+27x+4x+18\right)-\left(6x^2+x+12x+2\right)=x-1-x+6\)
\(\Leftrightarrow6x^2+31x+18-6x^2-x-12x-2=7\)
\(\Leftrightarrow18x+16=7\)
\(\Leftrightarrow18x=-9\)
\(\Leftrightarrow x=\frac{-1}{2}\)
\(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x-1\right)-\left(x-6\right)\)
\(3x\left(2x+9\right)+2\left(2x+9\right)-x\left(6x+1\right)-2\left(6x+1\right)=x-1-x+6\)
\(6x^2+27x+4x+18-6x^2-x-12x-2=5\)
\(6x^2+\left(27x+4x\right)+18-6x^2-\left(12x+x\right)-2=5\)
\(6x^2+31x+18-6x^2-13x-2=5\)
\(\left(6x^2-6x^2\right)+\left(31x-13x\right)+\left(18-2\right)=5\)
\(18x+16=5\)
\(18x=5+16\)
\(18x=21\)
\(x=21:18\)
\(x=\frac{7}{6}\)
Vậy \(x=\frac{7}{6}\)
P/s: Mình mới lớp 6 nên hi vọng bn xem bài của mik thật kĩ xem có sai sót không,cảm ơn.
Tìm x biết
1) \(\left(2x+3\right)\left(x-4\right)+\left(x-5\right)\left(x-2\right)=\left(3x-5\right)\left(x-4\right)\)
2)\(\left(8x-3\right)\left(3x+2\right)-\left(4x+7\right)\left(x+4\right)=\left(2x+1\right)\left(5x+1\right)-33\)
3)\(6x\left(3x+5\right)-2x\left(9x-2\right)+\left(17-x\right)\left(x-1\right)+x\left(x-18\right)-17x^2=0\)
4)\(\left(x-1\right)\left(x+2\right)-\left(x-3\right)+5x-7=0\)
Giúp mình nha. Camon nhiều
a) làm tính chia
\(\left[5\left(x-y\right)^4-3\left(x-y\right)^3+4\left(x-y\right)^2\right]:\left(y-x\right)^2\)
b) tìm \(x\)
\(\left(4x^4-3x^3\right):\left(-x^3\right)+\left(15x^2+6x\right):3x=0\)
ghi chú: đừng làm tắt được ko ạ?
b: Ta có: \(\left(4x^4-3x^3\right):\left(-x^3\right)+\left(15x^2+6x\right):3x=0\)
\(\Leftrightarrow-4x+3+5x+2=0\)
\(\Leftrightarrow x=-5\)
BÀI 6 tìm x
1,\(2x\left(x-5\right)-\left(3x+2x^2\right)=0\) 2,\(x\left(5-2x\right)+2x\left(x-1\right)=13\)
3,\(2x^3\left(2x-3\right)-x^2\left(4x^2-6x+2\right)=0\) 4,\(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
5,\(6x^2-\left(2x-3\right)\left(3x+2\right)=1\) 6,\(2x\left(1-x\right)+5=9-2x^2\)
1: \(\Leftrightarrow2x^2-10x-3x-2x^2=0\)
=>-13x=0
=>x=0
2: \(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
=>3x=13
=>x=13/3
3: \(\Leftrightarrow4x^4-6x^3-4x^3+6x^3-2x^2=0\)
=>-2x^2=0
=>x=0
4: \(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
=>-8x=6-14=-8
=>x=1
`1)2x(x-5)-(3x+2x^2)=0`
`<=>2x^2-10x-3x-2x^2=0`
`<=>-13x=0`
`<=>x=0`
___________________________________________________
`2)x(5-2x)+2x(x-1)=13`
`<=>5x-2x^2+2x^2-2x=13`
`<=>3x=13<=>x=13/3`
___________________________________________________
`3)2x^3(2x-3)-x^2(4x^2-6x+2)=0`
`<=>4x^4-6x^3-4x^4+6x^3-2x^2=0`
`<=>x=0`
___________________________________________________
`4)5x(x-1)-(x+2)(5x-7)=0`
`<=>5x^2-5x-5x^2+7x-10x+14=0`
`<=>-8x=-14`
`<=>x=7/4`
___________________________________________________
`5)6x^2-(2x-3)(3x+2)=1`
`<=>6x^2-6x^2-4x+9x+6=1`
`<=>5x=-5<=>x=-1`
___________________________________________________
`6)2x(1-x)+5=9-2x^2`
`<=>2x-2x^2+5=9-2x^2`
`<=>2x=4<=>x=2`
Rút gọn biểu thức:
\(\frac{1}{2}x^2.\left(6x-3\right)-x.\left(x^2+\frac{1}{2}\right)+\frac{1}{2}.\left(x+4\right)\)
Tìm x, biết:
\(2x.\left(x-5\right)-x\left(3+2x\right)=26\)
\(3x^3-\frac{3}{2}x^2-x^3-\frac{1}{2}x+\frac{1}{2}x+2=2x^3-\frac{3}{2}x^2+2\)
\(2x^2-10x-3x-2x^2=26\)
-13x=26
x=-2
Rút gọn biểu thức:
\(\frac{1}{2}x^2.\left(6x-3\right)-x\left(x^2+\frac{1}{2}\right)+\frac{1}{2}\left(x+4\right)\)
Tìm x, biết:
\(2x.\left(x-5\right)-x\left(3+2x\right)=26\)