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a: =>4/3x=7/9-4/9=1/3
=>x=1/4
b: =>5/2-x=9/14:(-4/7)=-9/8
=>x=5/2+9/8=29/8
c: =>3x+3/4=8/3
=>3x=23/12
hay x=23/36
d: =>-5/6-x=7/12-4/12=3/12=1/4
=>x=-5/6-1/4=-10/12-3/12=-13/12
1) \(\Rightarrow\left[{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)
2) \(\Rightarrow5\left(x-2\right).3\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=-2\end{matrix}\right.\)
3) \(\Rightarrow2\left(x-4\right)\left(x-7\right)=0\Rightarrow\left[{}\begin{matrix}x=4\\x=7\end{matrix}\right.\)
a) => 4/3x = 7/9 - 4/9 = 1/3
=> x = 1/3 : 4/3 = 1/4
b) => 5/2 - x = 9/14 : (-4/7) = -9/8
=> x = 5/2 - (-9/8) = 5/2 + 9/8 = 29/8
c) => 3x = 2 và 2/3 - 3/4 = 8/3 - 3/4 = 23/12
=> x = 23/12 : 3 = 23/36
D) => -5/6 - x = 1/4
=> x = -5/6 - 1/4 = -13/12
a) \(\dfrac{4}{9}+\dfrac{4}{3}x=\dfrac{7}{9}\)
\(\dfrac{4}{3}x=\dfrac{7}{9}-\dfrac{4}{9}=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}:\dfrac{4}{3}\)
\(x=\dfrac{1}{4}\)
b) \(\left(\dfrac{5}{2}-x\right)\left(-\dfrac{4}{7}\right)=\dfrac{9}{14}\)
\(\dfrac{5}{2}-x=\dfrac{9}{14}:\left(-\dfrac{4}{7}\right)=-\dfrac{9}{8}\)
\(x=\dfrac{5}{2}-\left(-\dfrac{9}{8}\right)\)
\(x=\dfrac{29}{8}\)
c) \(3x+\dfrac{3}{4}=2\dfrac{2}{3}\)
\(3x+\dfrac{3}{4}=\dfrac{8}{3}\)
\(3x=\dfrac{8}{3}-\dfrac{3}{4}=\dfrac{23}{12}\)
\(x=\dfrac{23}{12}:3\)
\(x=\dfrac{23}{36}\)
d) \(-\dfrac{5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
\(-\dfrac{5}{6}-x=\dfrac{1}{4}\)
\(x=-\dfrac{5}{6}-\dfrac{1}{4}\)
\(x=-\dfrac{13}{12}\)
\(3^x+3^{x+2}=\left(-3\right)^3.\left(-10\right)\\ \Leftrightarrow3^x+9.3^x=270\\ \Leftrightarrow10.3^x=270\\ \Leftrightarrow3^x=27\\ \Leftrightarrow3^x=3^3\\ \Leftrightarrow x=3\)
\(\Rightarrow3^x\left(1+3^2\right)=3^3\cdot10\\ \Rightarrow3^x\cdot10=3^3\cdot10\\ \Rightarrow x=3\)
\(\text{Cx khá đơn giản nhưng a giải chi tiết luôn nha}\)
\(1.\)
\(5\left(x+4\right)=25x\)
\(\Leftrightarrow5x+20=25x\)
\(\Leftrightarrow5x-25x=-20\)\(\text{(chuyển vế)}\)
\(\Leftrightarrow-20x=-20\)
\(\Leftrightarrow x=1\)
\(2.\)
\(-\frac{3}{6}=\frac{25}{2x-1}\)
\(\Leftrightarrow-\frac{1}{2}=25.\frac{1}{2x-1}\)
\(\Leftrightarrow\frac{1}{2x-1}=-\frac{1}{2}:25=-\frac{1}{50}\)
\(3.\)\(\text{(tương tự)}\)
\(\Leftrightarrow-50=2x-1\)\(\text{(nhân chéo)}\)
\(\Leftrightarrow x=-50+1=-49\)
\(4.\)
\(5\left(x-4\right)=3x+8\)
\(\Leftrightarrow5x-20=3x+8\)
\(\Leftrightarrow5x-3x=20+8\)
\(\Leftrightarrow2x=28\)
\(\Leftrightarrow x=28:2=14\)
1) 5.(x+4)=25x
5x+20=25x
20=25x-5x
20=20x
x=1
2) \(\frac{-3}{6}=\frac{25}{2x-1}\)
-3.(2x-1)=6.25
-6x+3=150
-6x=147
x=-24,5
câu 3,4 lm tương tự nha Nhớ đấy!!!!