tìm x biết
x2-5x+10=0
tìm x biết
x2+5x=0
phân tích đa thức sau thành nhân tử
x2-2x-xy+2y
HELP 28 phút nữa thi rồi
\(x^2+5x=0\Leftrightarrow x\left(x+5\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-5\end{matrix}\right.\)
\(x^2-2x-xy+2y=\left(x^2-xy\right)-2\left(x-y\right)=x\left(x-y\right)-2\left(x-y\right)=\left(x-y\right)\left(x-2\right)\)
Tìm số nguyên x. biết
x2=-25
\(x^2=-25\)
Vì \(x^2\ge0\forall x\)
Mà \(x^2=-25\) (vô lí)
Vậy: \(x\in\varnothing\)
tìm x: x(x-2)-5x+10=0
x(x-2)-5x+10=0
x(x-2)-5(x-2)=0
(x-5)(x-2)=0
x-5=0 hoặc x-2=0
x=5 hoặc x=2
<=> x^2-2x-5x+10=0
<=>x^2-7x+10=0
<=>(x-5).(x-2)=0 ( dùng cách bấm nghiệm bằng máy tính mode-5-3 , rồi nhập hệ số )
<=>x-5=0 hoặc x-2=0
<=>x=5 <=>x=2
Vậy PT có nghiệm là x=5 ; x=2
x(x-2) -5x +10 =0
x(x-2) -5x =10
x = 10:5
x=2
tìm x : I x + 3 I+ 10 - 5x = 0
`|x+3|+10-5x=0`
`<=>|x+3|=5x-10(x>=2)`
`+)x+3=5x-10`
`<=>4x=13`
`<=>x=13/4(tm)`
`+)x-3=10-5x`
`<=>6x=13`
`<=>x=13/6(tm)`
Vậy `S={13/4,13/6}`
\(\left|x+3\right|+10-5x=0\)
\(\Leftrightarrow\left|x+3\right|=5x-10\)
\(\Leftrightarrow\left\{{}\begin{matrix}5x-10\ge0\\\left[{}\begin{matrix}x+3=5x-10\\x+3=10-5x\end{matrix}\right.\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x\ge2\\\left[{}\begin{matrix}x=\dfrac{13}{4}\left(N\right)\\x=\dfrac{7}{6}\left(L\right)\end{matrix}\right.\end{matrix}\right.\)
Giải:
\(\left|x+3\right|+10-5x=0\)
\(\Rightarrow\left|x+3\right|=5x-10\)
\(\Rightarrow\left[{}\begin{matrix}5x-10=x+3\\5x-10=x-3\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{13}{4}\\x=\dfrac{7}{4}\end{matrix}\right.\)
Vậy \(x\in\left\{\dfrac{13}{4};\dfrac{7}{4}\right\}\)
Chúc bạn học tốt!
tìm x : I x + 3 I+ 10 - 5x = 0
`|x+3|+10-5x=0`
`<=>|x+3|=5x-10(x>=2)`
`+)x+3=5x-10`
`<=>4x=13`
`<=>x=13/4(tm)`
`+)x-3=10-5x`
`<=>6x=13`
`<=>x=13/6(tm)`
Vậy `S={13/4,13/6}`
TH1: `x+3>=0 <=> x>=-3`
`x+3+10-5x=0`
`-4x=-13`
`x=13/4` (TM)
TH2: `x+3<0 <=> x<-3`
`-x-3+10-5x=0`
`-6x=-7`
`x=7/6` (L)
Vậy `x=13/4`
tìm X
(5x - 10) . (6x + 12) = 0
\(\Leftrightarrow x\in\left\{2;-2\right\}\)
\(\Rightarrow\left(x-2\right)\left(x+2\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
(5x - 10) . (6x + 12) = 0
=>(5x - 10) = 0 hoặc (6x + 12) = 0
* TH1: (5x - 10) = 0 * TH2: (6x + 12) = 0
=>x = 2 => x = -2
Vậy x=2 hoặc x = -2
Tìm x biết:
\(a) x^2+3x-10=0 \)
\(b) x^2-5x-6=0\)
\(c) 2x^2+3x-2=0\)
a: Ta có: \(x^2+3x-10=0\)
\(\Leftrightarrow\left(x+5\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=2\end{matrix}\right.\)
b: Ta có: \(x^2-5x-6=0\)
\(\Leftrightarrow\left(x-6\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-1\end{matrix}\right.\)
3x(x-2)+10-5x=0
TÌM X
3x( x - 2 ) + 10 - 5x = 0
<=> 3x( x - 2 ) - ( 5x - 10 ) = 0
<=> 3x( x - 2 ) - 5( x - 2 ) = 0
<=> ( x - 2 )( 3x - 5 ) = 0
<=> \(\orbr{\begin{cases}x-2=0\\3x-5=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=\frac{5}{3}\end{cases}}\)
Tìm x biết:
a) 2x2 - 3x - 2 = 0.
b) 3x2 - 7x - 10 = 0.
c) 2x2 - 5x + 3 = 0.
a) 2x2 - 3x - 2 = 0.
<=> (2x + 1)(x - 2) = 0
<=> 2x + 1 = 0 hoặc x - 2 = 0
<=> x = -1/2 hoặc x = 2
b) 3x2 - 7x - 10 = 0.
<=> (x + 1)(3x - 10) = 0
<=> x = -1 hoặc x = 10/3
c) 2x2 - 5x + 3 = 0.
<=> (x - 1)(2x - 3) = 0
<=> x = 1 hoặc x = 3/2
Tìm x:
2x.(x+1)-5x-10=0
2x( x + 1 ) - 5x - 10 = 0
<=> 2x2 + 2x - 5x - 10 = 0
<=> 2x2 - 3x - 10 = 0
<=> 2( x2 - 3/2x + 9/16 ) - 89/8 = 0
<=> 2( x - 3/4 )2 = 89/8
<=> ( x - 3/4 )2 = 89/16
<=> \(\left(x-\frac{3}{4}\right)^2=\left(\pm\sqrt{\frac{89}{16}}\right)^2=\left(\pm\frac{\sqrt{89}}{4}\right)^2\)
<=> \(\orbr{\begin{cases}x-\frac{3}{4}=\frac{\sqrt{89}}{4}\\x-\frac{3}{4}=-\frac{\sqrt{89}}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{3+\sqrt{89}}{4}\\x=\frac{3-\sqrt{89}}{4}\end{cases}}\)