Tách một hạng tử. Tìm x:
1/(x—3)3—5(x—2)+5=0
2/(2x—1)2—3(x—2)(x+2)—25=0
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\(x^2-x-1=0\)
\(\Leftrightarrow\left(x^2-2\cdot\frac{1}{2}\cdot x+\frac{1}{4}\right)-\frac{5}{4}=0\)
\(\Leftrightarrow\left(x-\frac{1}{2}\right)^2-\frac{5}{4}=0\)
\(\Leftrightarrow\left(x-\frac{1}{2}\right)^2=\frac{5}{4}\)
\(\Leftrightarrow x=\frac{\sqrt{5}}{2}+\frac{1}{2};x=\frac{-\sqrt{5}}{2}+\frac{1}{2}\)
\(x^2-2x-1=0\)
\(\Leftrightarrow\left(x^2-2x+1\right)-2=0\)
\(\Leftrightarrow\left(x-1\right)^2-2=0\)
\(\Leftrightarrow\left(x-1\right)^2=2\)
\(\Leftrightarrow x=\sqrt{2}+1;x=-\sqrt{2}+1\)
1, \(\left(x-1\right)\left(x+2\right)-\left(x-1\right)^2=0\)
\(\Leftrightarrow\left(x-1\right)\left[x+2-\left(x-1\right)\right]=0\)
\(\Leftrightarrow3\left(x-1\right)=0\Leftrightarrow x=1\)
2, \(\left(x-2\right)^2-3\left(x-2\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left[x-2-3\left(x+1\right)\right]=0\)
\(\Leftrightarrow\left(x-2\right)\left(-2x-5\right)=0\Leftrightarrow x=-\dfrac{5}{2};x=2\)
3, \(\left(5-2x\right)\left(2x+7\right)=4x^2-25=\left(2x-5\right)\left(2x+5\right)\)
\(\Leftrightarrow\left(5-2x\right)\left(2x+7\right)+\left(5-2x\right)\left(2x+5\right)=0\)
\(\Leftrightarrow\left(5-2x\right)\left(2x+7+2x+5\right)=0\Leftrightarrow\left(4x+12\right)\left(5-2x\right)=0\Leftrightarrow x=-3;x=\dfrac{5}{2}\)
1) Ta có: \(\left(x-1\right)\left(x+2\right)-\left(x-1\right)^2=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+2-x+1\right)=0\)
\(\Leftrightarrow x-1=0\)
hay x=1
2) Ta có: \(\left(x-2\right)^2-3\left(x-2\right)\left(x+1\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x-2-3x-3\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(-2x-5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{-5}{2}\end{matrix}\right.\)
1:
=>2x-3=0 hoặc 5/2-x=0
=>x=3/2 hoặc x=5/2
2: =>x=1/2+12=12,5
3: =>(2x+3/5-3/5)(2x+3/5+3/5)=0
=>2x(2x+6/5)=0
=>x=0 hoặc x=-3/5
4: =>-1/6x=-1/3
=>x=1/3:1/6=2
5: =>1/4:x=1/4
=>x=1
6: =>2/5x+11/15=1
=>2/5x=4/15
=>x=2/3
1.
\(\left(x-5\right)^2+3\left(x-5\right)=0\)
\(\Leftrightarrow\left(x-5\right)\left(x-5+3\right)=0\)
\(\Leftrightarrow\left(x-5\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=0\\x-2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=2\end{matrix}\right.\)
2.
\(\left(x^2-9\right)+2\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+3\right)+2\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x+5=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)
3.
\(\left(2x+1\right)^2+\left(x-1\right)\left(2x+1\right)=0\)
\(\Leftrightarrow\left(2x+1\right)\left(2x+1+x-1\right)=0\)
\(\Leftrightarrow\left(2x+1\right).3x=0\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=0\\2x+1=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=-\dfrac{1}{2}\end{matrix}\right.\)
4.
\(\left(x-1\right)\left(x+3\right)+\left(x+3\right)^2=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-1+x+3\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(2x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+3=0\\2x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-1\end{matrix}\right.\)
1.(x+2)(x-3)=0
\(\left[{}\begin{matrix}x+2=0\\x-3=0\end{matrix}\right.\)
=> x = 3 hoặc x = -2
2,(x-5)(7-x)=0
=>\(\left[{}\begin{matrix}x-5=0\\7-x=0\end{matrix}\right.\)
=> x = 5 hoặc x = 7
3.(2x + 3)(-x + 7)=0
=>\(\left[{}\begin{matrix}2x+3=0\\-x+7=0\end{matrix}\right.\)
=> x = -3/2 hoặc x = 7.
4.(-10x + 5 )(2x-8)=0
=>\(\left[{}\begin{matrix}-10x+5=0\\2x-8=0\end{matrix}\right.\)
=> x = 1/2 hoặc x=4
5.(x-1)(x+2)(x-3)=0
=>\(\left[{}\begin{matrix}x-1=0\\x+2=0\\x-3=0\end{matrix}\right.\)
=> \(\left[{}\begin{matrix}x=1\\x=-2\\x=3\end{matrix}\right.\)
Em ơi, với mấy bài có tích bằng 0 như này ta chỉ cần đặt từng trường hợp cho thừa số chứa biến x bằng 0; rồi giải phép tính là ra em nhé!
Mà cô có thắc mắc là đây là môn Toán, mình up lên môn Toán chứ sao lại môn Tiếng Anh bạn Kim nhỉ!
\(\left(x-3\right)^2-5\left(x-2\right)+5=0\\ \Leftrightarrow x^2-6x+9-5x+10+5=0\\ \Leftrightarrow x^2-11x+24=0\\ \Leftrightarrow\left(x-8\right)\left(x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=8\\x=3\end{matrix}\right.\)
\(\left(2x-1\right)^2-3\left(x-2\right)\left(x+2\right)-25=0\\ \Leftrightarrow4x^2-4x+1-3\left(x^2-4\right)-25=0\\ \Leftrightarrow4x^2-4x-24-3x^2+12=0\\ \Leftrightarrow x^2-4x-12=0\\ \Leftrightarrow\left(x-6\right)\left(x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)
a: Ta có: \(\left(x-3\right)^2-5\left(x-2\right)+5=0\)
\(\Leftrightarrow x^2-6x+9-5x+10+5=0\)
\(\Leftrightarrow x^2-11x+24=0\)
\(\Leftrightarrow\left(x-8\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=8\\x=3\end{matrix}\right.\)
b: Ta có: \(\left(2x-1\right)^2-3\left(x-2\right)\left(x+2\right)-25=0\)
\(\Leftrightarrow4x^2-4x+1-3x^2+12-25=0\)
\(\Leftrightarrow x^2-4x-12=0\)
\(\Leftrightarrow\left(x-6\right)\left(x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-2\end{matrix}\right.\)
tìm x biết:
(3x-1) [- 1/2x+5]=0
1/4+1/3:(2x-1)=-5
[2x+3/5]2 - 9/25=0
-5(x+1/5)-1/2(x-2/3)=3/2x - 5 /6
[x+1/2]x [2/3-2x]=0
17/2-|2x-3/4|=-7/4
2/3x-1/2x =5/12
(x+1/5)2+17/25=26/25
[x.44/7+3/7].11/5-3/7=-2
3[3x-1/2]+1/9=0
Toán lớp 6Tìm x
Trả lời Câu hỏi tương tự
Chưa có ai trả lời câu hỏi này,bạn hãy là người đâu tiên giúp nguyenvanhoang giải bài toán này !
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
a) \(\left(x+3\right)^2-\left(x-2\right)^3=\left(x+5\right)\left(x^2-5x+25\right)-108\)
\(\Leftrightarrow x^2+6x+9-x^2+4x-4=x^3-5x^2+25x+5x^2-25x+125-108\)
\(\Leftrightarrow x^3-10x+12=0\Leftrightarrow\left(x-2\right)\left(x^2+2x+6\right)=0\)
\(\Leftrightarrow x=2\)( do \(x^2+2x+6=\left(x+1\right)^2+4\ge4>0\))
1,\(\left(x-3\right)^3-5\left(x-2\right)+5=0\)
\(\Rightarrow\left(x-3\right)^3-5\left(x-3\right)=0\)
\(\Rightarrow\left(x-3\right)\left[\left(x-3\right)^2-5\right]=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\\left(x-3\right)^2-5=0\end{cases}}\)
\(\Rightarrow x=3\) hoặc \(x=\sqrt{5}+3\) hoặc \(x=-\sqrt{5}+3\)
Vậy........