(3x - 1 ) . (-1/2 x + 5 ) = 0
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15 tháng 3 2020
\(\left(4-3x\right)\left(10x-5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}4-3x=0\\10x-5=0\end{cases}\Rightarrow\orbr{\begin{cases}3x=4\\10x=5\end{cases}\Rightarrow}\orbr{\begin{cases}x=\frac{4}{3}\\x=\frac{1}{2}\end{cases}}}\)
\(\left(7-2x\right)\left(4+8x\right)=0\)
\(\Rightarrow\orbr{\begin{cases}7-2x=0\\4+8x=0\end{cases}\Rightarrow\orbr{\begin{cases}2x=7\\8x=-4\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{7}{2}\\x=-\frac{1}{2}\end{cases}}}}\)
rồi thực hiện đến hết ...
15 tháng 3 2020
Brainchild bé ngây thơ qus e , ko thực hiện đến hết như thế đc đâu :>
\(\left(x-3\right)\left(2x-1\right)=\left(2x-1\right)\left(2x+3\right)\)
\(2x^2-7x+3=4x^2+4x-3\)
\(2x^2-7x+3-4x^2-4x+3=0\)
\(-2x^2-11x+6=0\)
\(2x^2+11x-6=0\)
\(2x^2+12x-x-6=0\)
\(2x\left(x+6\right)-\left(x+6\right)=0\)
\(\left(x+6\right)\left(2x-1\right)=0\)
\(x+6=0\Leftrightarrow x=-6\)
\(2x-1=0\Leftrightarrow2x=1\Leftrightarrow x=\frac{1}{2}\)
\(3x-2x^2=0\)
\(x\left(2x-3\right)=0\)
\(x=0\)
\(2x-3=0\Leftrightarrow2x=3\Leftrightarrow x=\frac{3}{2}\)
Tự lm tiếp nha
17 tháng 11 2021
\(1,\Leftrightarrow x\left(x-9\right)=0\Leftrightarrow\left[{}\begin{matrix}x=9\\x=0\end{matrix}\right.\\ 2,\Leftrightarrow x^2-4x-x^2=7\Leftrightarrow-4x=7\Leftrightarrow x=-\dfrac{7}{4}\\ 3,\Leftrightarrow3x+2x-10=5\Leftrightarrow5x=15\Leftrightarrow x=3\\ 4,\Leftrightarrow\left(5x-1\right)\left(5x+1\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=-\dfrac{1}{5}\end{matrix}\right.\\ 5,\Leftrightarrow\left(x-2\right)\left(3x-5\right)=0\Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{5}{3}\end{matrix}\right.\\ 6,\Leftrightarrow\left(x-7\right)\left(3x+4\right)=0\Leftrightarrow\left[{}\begin{matrix}x=7\\x=-\dfrac{4}{3}\end{matrix}\right.\)
\(7,\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\\ 8,\Leftrightarrow\left(x-4\right)\left(10x+2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{5}\\x=4\end{matrix}\right.\\ 9,\Leftrightarrow2x^2-5x-2x^2=0\Leftrightarrow x=0\\ 10,\Leftrightarrow2x\left(x-2\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\\ 11,\Leftrightarrow\left(4x-3\right)\left(3-2x\right)=0\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=\dfrac{3}{2}\end{matrix}\right.\\ 12,\Leftrightarrow2x^2-10x-2x^2=3\Leftrightarrow-10x=3\Leftrightarrow x=-\dfrac{3}{10}\)
17 tháng 11 2021
\(1,\Leftrightarrow x\left(x-9\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=9\end{matrix}\right.\\ 2,\Leftrightarrow x^2-4x-x^2=7\\ \Leftrightarrow-4x=7\\ \Leftrightarrow x=\dfrac{-7}{4}\\ 3,\Leftrightarrow3x+2x-10=5\\ \Leftrightarrow5x=15\\ \Leftrightarrow x=3\\ 4,\Leftrightarrow\left(5x-1\right)\left(5x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{1}{5}\\x=-\dfrac{1}{5}\end{matrix}\right.\)
\(5,\Leftrightarrow\left(x-2\right)\left(3x-5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=2\\x=\dfrac{5}{3}\end{matrix}\right.\\ 6,\Leftrightarrow\left(3x+4\right)\left(x-7\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{4}{3}\\x=7\end{matrix}\right.\\ 7,\Leftrightarrow\left(2x-3\right)\left(2x+3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=-\dfrac{3}{2}\end{matrix}\right.\)
\(8,\Leftrightarrow10x\left(x-4\right)+2\left(x-4\right)=0\\ \Leftrightarrow\left(x-4\right)\left(10x+2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=4\\x=-\dfrac{1}{5}\end{matrix}\right.\\ 9,\Leftrightarrow2x^2-5x-2x^2=0\\ \Leftrightarrow-5x=0\\ \Leftrightarrow x=0\\ 10,\Leftrightarrow2x\left(x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\end{matrix}\right.\)
\(11,\Leftrightarrow\left(2x-3\right)\left(4x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=\dfrac{3}{4}\end{matrix}\right.\\ 12,\Leftrightarrow2x^2-10x-2x^2=3\\ \Leftrightarrow-10x=3\\ \Leftrightarrow x=-\dfrac{3}{10}\)
20 tháng 4 2020
a)
\(\left(4x-10\right)\cdot\left(24+5x\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}4x-10=0\\24+5x=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}4x=10\\5x=-24\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{5}{2}\\x=-\frac{24}{5}\end{matrix}\right.\)
Vậy \(S=\left\{\frac{5}{2};-\frac{24}{5}\right\}\)
b)
\(\left(2x-5\right)\left(3x-2\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}2x-5=0\\3x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{5}{2}\\x=\frac{2}{3}\end{matrix}\right.\)
Vậy \(S=\left\{\frac{5}{2};\frac{2}{3}\right\}\)
c)
\(\left(2x-1\right)\left(3x+1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}2x-1=0\\3x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{1}{2}\\x=-\frac{1}{3}\end{matrix}\right.\)
Vậy \(S=\left\{\frac{1}{2};-\frac{1}{3}\right\}\)
d)
\(x\left(2x-1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\\x=\frac{1}{2}\end{matrix}\right.\)
Vậy \(S=\left\{0;\frac{1}{2}\right\}\)
e) \(\left(5x+3\right)\left(x^2+4\right)\left(x-1\right)=0\)
Do \(x^2\ge0\) Nên \(x^2+4>0\)
\(\left(5x+3\right)\left(x^2+4\right)\left(x-1\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}5x+3=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\frac{3}{5}\\x=1\end{matrix}\right.\)
Vậy \(S=\left\{-\frac{3}{5};1\right\}\)
....... Còn lại cứ cho mỗi thừa số = 0 rồi tìm x như bình thường thôi bạn
20 tháng 4 2020
1. (4x - 10)(24 + 5x) = 0
\(\Leftrightarrow\left[{}\begin{matrix}4x-10=0\\24+5x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{5}{2}\\x=\frac{-24}{5}\end{matrix}\right.\)
Vậy S = {\(\frac{5}{2}\); \(\frac{-24}{5}\)}
2. (2x - 5)(3x - 2) = 0
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=0\\3x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{5}{2}\\x=\frac{2}{3}\end{matrix}\right.\)
Vậy S = {\(\frac{5}{2}\); \(\frac{2}{3}\)}
3. (2x - 1)(3x + 1) = 0
\(\Leftrightarrow\left[{}\begin{matrix}2x-1=0\\3x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{1}{2}\\x=\frac{-1}{3}\end{matrix}\right.\)
Vậy S = {\(\frac{1}{2}\); \(\frac{-1}{3}\)}
4. x(x2 - 1) = 0
\(\Leftrightarrow\) x(x - 1)(x + 1) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x-1=0\\x+1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)
Vậy S = {0; 1; -1}
5. (5x + 3)(x2 + 4)(x - 1) = 0
VÌ x2 + 4 > 0 với mọi x nên
\(\Rightarrow\left[{}\begin{matrix}5x+3=0\\x-1=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\frac{-3}{5}\\x=1\end{matrix}\right.\)
Vậy S = {\(\frac{-3}{5}\); 1}
6. (x - 1)(x + 2)(x + 3) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+2=0\\x+3=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\\x=-3\end{matrix}\right.\)
Vậy S = {1; -2; -3}
7. (x - 1)(x + 5)(-3x + 8) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\\x+5=0\\-3x+8=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-5\\x=\frac{8}{3}\end{matrix}\right.\)
Vậy S = {1; -5; \(\frac{8}{3}\)}
Chúc bn học tốt!!
14 tháng 2 2020
\(\left(3x+1\right)^2-x^2+8x-16=0\)
\(\Leftrightarrow\left(3x+1\right)^2-\left(x-4\right)^2=0\)
\(\Leftrightarrow\left(3x+1+x-4\right)\left(3x+1-x+4\right)=0\)
\(\Leftrightarrow\left(4x-3\right)\left(2x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}4x-3=0\\2x+5=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{4}\\x=\frac{-5}{2}\end{cases}}\)
14 tháng 2 2020
\(\left(3x+1\right)^2-x^2+8x-16=0\)
\(\Leftrightarrow\left(3x+1\right)^2-\left(x^2-8x+16\right)=0\)
\(\Leftrightarrow\left(3x+1\right)^2-\left(x-4\right)^2=0\)
\(\Leftrightarrow\left(3x+1+x-4\right)\left(3x+1-x+4\right)=0\)
\(\Leftrightarrow\left(4x-3\right)\left(2x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}4x-3=0\\2x+5=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{4}\\x=\frac{-5}{2}\end{cases}}\)
TT
1 tháng 3 2020
1. \(\Leftrightarrow\left(x-6\right)\left(x+7\right)+5\left(x-6\right)\left(3x-1\right)=0\)
\(\Leftrightarrow\left(x-6\right)\left[\left(x+7\right)+5\left(3x-1\right)\right]=0\)
\(\Leftrightarrow\left(x-6\right)\left(16x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-6=0\\16x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-\frac{1}{8}\end{matrix}\right.\)
TT
1 tháng 3 2020
4. \(\Leftrightarrow\left(x+5\right)^2\left(3x+2\right)^2-x^2\left(x+5\right)^2=0\)
\(\Leftrightarrow\left(x+5\right)^2\left[\left(3x+2\right)^2-x^2\right]=0\)
\(\Leftrightarrow\left(x+5\right)^2\left(2x+2\right)\left(4x+2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(x+5\right)^2=0\\2x+2=0\\4x+2=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x+5=0\\2x=-2\\4x=-2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=-1\\x=-\frac{1}{2}\end{matrix}\right.\)
\(\Leftrightarrow\hept{\begin{cases}3x-1=0\\\frac{-1}{2}x+5=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}3x=1\\\frac{-1}{2}x=-5\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x=\frac{1}{3}\\x=10\end{cases}}\)
Vậy ...
\(\left(3x-1\right)\left(-\frac{1}{2}x+5\right)=0\)
Xét 2 trường hợp:
TH1: 3x - 1 = 0
3x = 0 + 1
3x = 1
x = 1 : 3
x = \(\frac{1}{3}\)
TH2: \(-\frac{1}{2}x+5=0\)
\(-\frac{1}{2}x=0-5\)
\(-\frac{1}{2}x=-5\)
\(\left(-\frac{1}{2}x\right)\left(-2\right)=\left(-5\right)\left(-2\right)\)
x = 10
\(\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=10\end{cases}}\)