(x-4)/-5=(1-2x)/3
giúp và giải thích cho mình từng bước vs ạ:(
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\(\left(3x+2\right)\left(x-1\right)-3\left(x+1\right)\left(x-2\right)=4\)
\(\Rightarrow3x^2-3x+2x-2-\left(3x+3\right)\left(x-2\right)=4\)
\(\Rightarrow3x^2-3x+2x-2-\left(3x^2-6x+3x-6\right)=4\)
\(\Rightarrow3x^2-3x+2x-2-3x^2+6x-3x+6=4\)
\(\Rightarrow2x+4=4\)
\(\Rightarrow x=0\)
\(a.\left(2x-1\right)^2-\left(4x-3\right)\left(x+5\right)=0\) \(\Leftrightarrow4x^2-4x+1-\left(4x^2+17x-15\right)=0\)
\(\Leftrightarrow-21x+16=0\Leftrightarrow x=\dfrac{16}{21}\) . Vậy ...
b.\(x\left(x-1\right)=3\left(x-1\right)\Leftrightarrow\left(x-3\right)\left(x-1\right)=0\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\) . Vậy ...
c.\(\left(x-1\right)\left(3x-7\right)=\left(x-1\right)\left(x+3\right)\Leftrightarrow\left(x-1\right)\left(3x-7-x-3\right)=0\)
\(\Leftrightarrow2\left(x-1\right)\left(x-5\right)=0\Leftrightarrow\left[{}\begin{matrix}x=1\\x=5\end{matrix}\right.\) . Vậy ...
d.\(\left(x-3\right)^2+2x-6=0\Leftrightarrow\left(x-3\right)\left(x-3+2\right)=0\) \(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=1\end{matrix}\right.\) . Vậy ...
\(x^2+4x+5=2\sqrt{2x+3}\)
\(ĐK:x\ge-\dfrac{3}{2}\)
\(pt\Leftrightarrow(2x+3-2\sqrt{2x+3}+1)+x^2+2x+1=0\)
\(\Leftrightarrow\left(\sqrt{2x+3}-1\right)^2=-\left(x+1\right)^2\)
Vì \(\left(\sqrt{2x+3}-1\right)^2\ge0;-\left(x+1\right)^2\le0\forall x\)
\(\Rightarrow\left\{{}\begin{matrix}(\sqrt{2x+3}-1)^2=0\\\left(x+1\right)^2=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\sqrt{2x+3}-1=0\\x+1=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\sqrt{2x+3}=1\\x=-1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}2x+3=1\\x=-1\end{matrix}\right.\Leftrightarrow x=-1\left(tm\right)}\)
\(\Leftrightarrow x=-1\left(tm\right)\)
Vậy, pt có nghiệm duy nhất là x=-1
\(\frac{x-4}{-5}=\frac{1-2x}{3}\)
Nhân cả 2 vế với 15 ,ta được:
\(\frac{15.\left(x-4\right)}{-5}=\frac{15.\left(1-2x\right)}{3}\)
\(\Leftrightarrow\left(-3\right).\left(x-4\right)=5.\left(1-2x\right)\)
\(\Leftrightarrow-3x+12=5-10x\)
\(\Leftrightarrow-3x+10x=5-12\)
\(\Leftrightarrow7x=-7\)
\(\Leftrightarrow x=-1\)
Vậy x=-1
(𝑥−4)/−5=(1−2𝑥)/3
−15⋅𝑥−4−5=−15⋅−2𝑥+13
−15⋅𝑥−4−5=−15⋅−2𝑥+13
3(𝑥−4)=−5(−2𝑥+1)
3(x-4)=-5(-2x+1)
3(𝑥−4)=−5(−2𝑥+1)
3𝑥−12=−5(−2𝑥+1)
3𝑥−12=−5(−2𝑥+1)
3𝑥−12=10𝑥−5
𝑥 = -1