a,5x(4+6*x)=290
b,(15x24-x):0,25=100:1/4
Các bn giúp mình nha
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\(60+x-34=43\Rightarrow x=43+34-60=17\)
\(23x-6.23+69x=230\)
\(\Rightarrow23x+69x=230+6.23\)
\(\Rightarrow92x=368\Rightarrow x=368:92\Rightarrow x=4\)
\(\left(15.24-x\right):0,25=100:0,25\)
\(\Rightarrow\left(360-x\right)=100:0,25.0,25\)
\(\Rightarrow360-x=100\Rightarrow x=360-100=260\)
\(\left(7x+8\right):5=10\Rightarrow\left(7x+8\right)=10.5\)
\(\Rightarrow7x+8=50\Rightarrow7x=50-8\Rightarrow7x=42\Rightarrow x=42:7=6\)
\(280:\left(7+3x\right)=4\Rightarrow\left(7+3x\right)=280:4\)
\(\Rightarrow7+3x=70\Rightarrow3x=70-7\Rightarrow3x=63\Rightarrow x=63:3=21\)
\(\left(x+5\right)x19:13=57\)
\(\Rightarrow\left(x+5\right)x19=57.13\)
\(\Rightarrow\left(x+5\right)=741:19\Rightarrow x+5=39\Rightarrow x=39-5=34\)
\(4\left(36-4x\right)=64\)
\(\Rightarrow\left(36-4x\right)=64:4\)
\(\Rightarrow36-4x=16\)
\(\Rightarrow4x=36-16\Rightarrow4x=20\Rightarrow x=20:4=5\)
\(\left(7,6:1,9\right)x=3,2\)
\(\Rightarrow4x=3,2\Rightarrow x=3,2:4=0,8\)
\(\left(x:2+50\right):5=12\)
\(\Rightarrow x:2+50=12.5\)
\(\Rightarrow x:2=60-50\Rightarrow x:2=10\Rightarrow x=10.2=20\)
bạn viết rõ đề ra nhé
b, \(\left|4x-8\right|=1-x\)ĐK : \(x\le1\)
TH1 : \(4x-8=1-x\Leftrightarrow5x=9\Leftrightarrow x=\dfrac{9}{5}\)( ktm )
TH2 : \(4x-8=x-1\Leftrightarrow3x=7\Leftrightarrow x=\dfrac{7}{3}\)( ktm )
b) Ta có: \(\left|4x-8\right|=1-x\)
\(\Leftrightarrow\left[{}\begin{matrix}4x-8=1-x\left(x\ge2\right)\\4x-8=x-1\left(x< 2\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}4x+x=1+8\\4x-x=-1+8\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}5x=9\\3x=7\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{5}\left(loại\right)\\x=\dfrac{7}{3}\left(loại\right)\end{matrix}\right.\)
\(A=2\times4+4\times6+...+98\times100\)
\(A=2.2+2.12+...+2.149\)
\(A=2.\left(2+12+...+149\right)\)
Tự làm nốt( dấu x = dấu chấm )
a, \(5\cdot\left(4+6\cdot x\right)=290\Rightarrow4+6\cdot x=290:5\Rightarrow4+6\cdot x=58\)
\(\Rightarrow6\cdot x=58-4\Rightarrow6\cdot x=54\Rightarrow x=54:6\Rightarrow x=9\)
b, \(\left(15\cdot24-x\right):0,25=100:\frac{1}{4}\Rightarrow\left(15\cdot24-x\right):\frac{1}{4}=100:\frac{1}{4}\)
\(\Rightarrow\left(15\cdot24-x\right):\frac{1}{4}=100\cdot\frac{4}{1}\Rightarrow\left(15\cdot24-x\right):\frac{1}{4}=400\)
\(\Rightarrow15\cdot24-x=400\cdot\frac{1}{4}\Rightarrow15\cdot24-x=100\Rightarrow360-x=100\)
\(\Rightarrow x=360-100\Rightarrow x=260\)
dấu sao là j vậy bn