(x-3)×(5-×)=0
Tìm x ≥ 0, biết:
a) 2x-7\(\sqrt{x}\)+3=0
b) 3\(\sqrt{x}\)+5 < 6
c) x-3\(\sqrt{x}\) -10 < 0
d) x- 5\(\sqrt{x}\) +6 = 0
e) x+ 5\(\sqrt{x}\) -14 < 0
\(\left(a\right):2x-7\sqrt{x}+3=0\left(x\ge0\right)\\ < =>\left(2x-6\sqrt{x}\right)-\left(\sqrt{x}-3\right)=0\\ < =>2\sqrt{x}\left(\sqrt{x}-3\right)-\left(\sqrt{x}-3\right)=0\\ < =>\left(2\sqrt{x}-1\right)\left(\sqrt{x}-3\right)=0\\ =>\left[{}\begin{matrix}2\sqrt{x}-1=0\\\sqrt{x}-3=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=\dfrac{1}{4}\left(TM\right)\\x=9\left(TM\right)\end{matrix}\right.\)
\(\left(b\right):3\sqrt{x}+5< 6\\ < =>3\sqrt{x}< 1\\ < =>\sqrt{x}< \dfrac{1}{3}\\ < =>0\le x< \dfrac{1}{9}\)
\(\left(c\right):x-3\sqrt{x}-10< 0\\ < =>\left(x-5\sqrt{x}\right)+\left(2\sqrt{x}-10\right)< 0\\ < =>\sqrt{x}\left(\sqrt{x}-5\right)+2\left(\sqrt{x}-5\right)< 0\\ < =>\left(\sqrt{x}-5\right)\left(\sqrt{x}+2\right)< 0\\ =>\left\{{}\begin{matrix}\sqrt{x}-5< 0\\\sqrt{x}+2>0\end{matrix}\right.\\ < =>\left\{{}\begin{matrix}0\le x< 25\\x\ge0\end{matrix}\right.< =>0\le x< 25\)
\(\left(d\right):x-5\sqrt{x}+6=0\left(x\ge0\right)\\ < =>\left(x-2\sqrt{x}\right)-\left(3\sqrt{x}-6\right)=0\\ < =>\sqrt{x}\left(\sqrt{x}-2\right)-3\left(\sqrt{x}-2\right)=0\\ < =>\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)=0\\ =>\left[{}\begin{matrix}\sqrt{x}-3=0\\\sqrt{x}-2=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=9\\x=4\end{matrix}\right.\left(TM\right)\)
\(\left(e\right):x+5\sqrt{x}-14< 0\\ < =>\left(x+7\sqrt{x}\right)-\left(2\sqrt{x}+14\right)< 0\\ < =>\sqrt{x}\left(\sqrt{x}+7\right)-2\left(\sqrt{x}+7\right)< 0\\ < =>\left(\sqrt{x}-2\right)\left(\sqrt{x}+7\right)< 0\\ =>\left\{{}\begin{matrix}\sqrt{x}+7>0\\\sqrt{x}-2< 0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x\ge0\\0\le x< 4\end{matrix}\right.< =>0\le x< 4\)
Tìm x biết:
a) (x - 3)2 - 5.(x - 2) + 5 = 0.
b) (2x - 1)2 - 3.(x - 2).(x + 2) - 25 = 0.
c) (x - 1)3 - x2.(x - 2) + 5 = 0.
d) x2 - 4x + 5 = 0.
a) (x - 3)2 - 5.(x - 2) + 5 = 0.
<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0
<=> x^2 - 11x + 24 = 0
<=> (x-3)(x-8)=0
<=> x = 3 hoặc x = 8
b) (2x - 1)2 - 3.(x - 2).(x + 2) - 25 = 0.
<=> 4x^2 - 4x + 1 - 3x^2 + 12 - 25 = 0
<=> x2 - 4x - 12 = 0
<=> (x+2)(x-6) = 0
<=> x = -2 hoặc x = 6
d) x2 - 4x + 5 = 0.
<=> (x - 2)2 = -1 (vô lý)
Vậy phương trình vô nghiệm
\(1,\)
\(2x\left(x-3\right)-\left(3-x\right)=0\)
\(\Leftrightarrow2x\left(x-3\right)+\left(x-3\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(x-3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=0\\x-3=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=3\end{cases}}\)
\(2,\)
\(3x\left(x+5\right)-6\left(x+5\right)=0\)
\(\Leftrightarrow\left(3x-6\right)\left(x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}3x-6=0\\x+5=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-5\end{cases}}\)
\(3,\)
\(x^4-x^2=0\)
\(\Leftrightarrow x^2\left(x^2-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x^2=0\\x^2-1=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=\pm1\end{cases}}\)
\(4,\)
\(x^2-2x=0\)
\(\Leftrightarrow x\left(x-2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-2=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x=2\end{cases}}\)
\(5,\)
\(x\left(x+6\right)-10\left(x-6\right)=0\)
\(\Leftrightarrow x^2+6x-10x+60=0\)
\(\Leftrightarrow x^2-4x+60=0\)
\(\Leftrightarrow x^2-4x+4+56=0\)
\(\Leftrightarrow\left(x-2\right)^2=-56\)(Vô lý)
=> Phương trình vô nghiệm
|x-3| + |y-2x | =0
|x| + 3|2x -x ² | =0
|5x ² -5 | + 4|y-7 | =0
||x +1 | + |y-5 |=0
|x ² -1| + |y-1| =0
|x-1 | +|x ²-x |=0
a) Ta có: \(\left|x-3\right|+\left|y-2x\right|=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-3=0\\y-2x=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=2x=2\cdot3=6\end{matrix}\right.\)
bạn tin lúc trước tớ nói không tớ sai ở chổ 1x0 đóooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooo
|x-3| + |y-2x | =0 |x| + 3|2x -x ² | =0 |5x ² -5 | + 4|y-7 | =0 ||x +1 | + |y-5 |=0 |x ² -1| + |y-1| =0 |x-1 | +|x ²-x |=0
a) Ta có: \(\left|x-3\right|+\left|y-2x\right|=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-3=0\\y-2x=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=2x=2\cdot3=6\end{matrix}\right.\)
a, (x+3)(x+5)=0
b, (x-1)5-1=0
c,(x-2018) ^x+2019=1
(x-5)^3-(x-5)^2=0
E = 3^2020 - 3^2019 + 3^2018-......+3^2 - 3
a) (x+3)(x+5)=0
=>x+3=0 hoặc x+5=0
=>x=-3 hoặc -5
b) (x-1).5-1=0
=>5x-5-1=0
=>5x-6=0
=>5x=6
=>x=6/5
c)
Tìm x nguyên biết :
a) (x^2 -5)×(x^2 +1)=0
b)(x+3)×(x^2+1)=0
c)(x+5)×(x^2+1)<0
d)(x+5)×(x^2-4)=0
e)(x-2)×(-x^2-4)>0
g)(x^2+2)×(x+3)>0
h)(x+4)×|x+5|>0
i)(x+3)×(x-5)>0
\(\left(x^2-5\right)\left(x^2+1\right)=0\)
<=> \(\hept{\begin{cases}x^2-5=0\\x^2+1=0\end{cases}}\)
<=> \(\hept{\begin{cases}x^2=5\\x^2=-1\end{cases}}\)
<=> \(\hept{\begin{cases}x=\sqrt{5};x=-\sqrt{5}\\x\in\varnothing\end{cases}}\)
câu còn lại tương tự nha
( x + 5 ) ( x + 3 ) > 0
( x + 6 ) ( x - 5 ) <0
( 2x - 6 ) ( x + 5 ) < 0
gửi Khương Minh Quang
<=>(3-x)(5-x)x=(x-5)(x-3)x
=>x-5=0
=>x=5
=>x-3=0
=>x=3
=> x=0
vậy x có 3 trường hợp : TH1:x=0;
TH2:x=3 ;
TH3:x=5
bài này ko viết đầu bài đâu chép từ dấu " <=>" ấy nhé
Tìm x thuộc Z:
1. x.(x+7) = 0
2 . (x+12).(x-3)= 0
3. (-x+5).(3-x)=0
4. x.(2+x).(7-x)=0
5. (x-1).(x+2).(-x-3)=0
Giải được 3/5 mình sẽ tick nhưng mong các bạn giải hết cho mình.
bài 1: x.(x+7) = 0
Th1:x=0 Th2:x+7=0
=>x=-7
bài 2 (x+12).(x-3)= 0
Th1:x+12=0 Th2:x-3=0
=>x=-12 =>x=3
bài 3 (-x+5).(3-x)=0
Th1 (-x)+5=0 Th2:3-x=0
=>-x=-5 =>x=3
bài 4 x.(2+x).(7-x)=0
Th1:x=0 Th3:7-x=0
Th2:2+x=0 =>x=7
=>x=-2
bài 5 (x-1).(x+2).(-x-3)=0
Th1:x-1=0 Th2:x+2=0
=>x=1 =>x=-2
Th3:-x-3=0
=>-x=-3