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a) 47 - [ (45.24 - 52.12) : 14 ]
= 47 - ( 420 : 14 )
= 47 - 30
= 17
\(a,x-\left\{x-\left[x-\left(-x+1\right)\right]\right\}=1\)
\(=>x-\left\{x-\left[x+x+1\right]\right\}=1\)
\(=>x-\left\{x-x-x-1\right\}=1\)
\(=>x-x+x+x+1=1\)
\(=>2x=1-1=0\)
\(=>x=0\)
\(b,x-\left\{-x+\left(x+3\right)-\left(x-2\right)\right\}=0\)
\(=>x-\left\{-x+x+3-x+2\right\}=0\)
\(=>x-\left(3-x+2\right)=0\)
\(=>x-3+x-2=0\)
\(=>2x=5\)
\(=>x=\frac{5}{2}\)
\(c,x+\left\{\left(x-3\right)-\left[\left(x+3\right)-\left(-x-2\right)\right]\right\}=x\)
\(=>\left\{\left(x-3\right)-\left[x+3+x+2\right]\right\}=0\)
\(=>\left\{x-3-x-3-x-2\right\}=0\)
\(=>-x=3+3+2=8\)
\(=>x=-8\)
1
\(\left(x-2\right):2.3=6\)
\(\Leftrightarrow\left(x-2\right):2=2\)
\(\Leftrightarrow\left(x-2\right)=4\)
\(\Leftrightarrow x=4+2=6\)
c) ta có
\(\left[\left(2x+1\right)+1\right]m:2=625\)
\(\Leftrightarrow\left[\left(2x+1\right)+1\right]\left\{\left[\left(2x+1\right)-1\right]:2+1\right\}=1250\)
\(\Leftrightarrow\left(2x+1\right)^2+1-1:2+1=1250\)
\(\Leftrightarrow\left(2x+1\right)^2+1-2+1=1250\)
\(\Leftrightarrow\left(2x+1\right)^2+1-2=1249\)
\(\Leftrightarrow\left(2x+1\right)^2+1=1251\)
\(\Leftrightarrow\left(2x+1\right)^2=1250\)
...
2
\(\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{7}{4}-\frac{1}{2}\)
\(\Leftrightarrow\left(x-\frac{1}{2}\right).\frac{5}{3}=\frac{5}{4}\)
\(\Leftrightarrow\left(x-\frac{1}{2}\right)=\frac{5}{4}:\frac{5}{3}\)
\(\Leftrightarrow\left(x-\frac{1}{2}\right)=\frac{5}{4}.\frac{3}{5}\)
\(\Leftrightarrow x-\frac{1}{2}=\frac{3}{4}\)
\(\Leftrightarrow x=\frac{3}{4}+\frac{1}{2}=\frac{5}{4}\)
từ 1 đến 996 có 996 chữ số nếu chia thành 4 số 1 cặp thì có 249 cặp
x[(1+2-3-4)+(5+6-7-8)+...+(993+994-995-996)+997]=36
x.[(-4).249+997]=36
x.1=36
x=36:1
x=36
\(-2.\left(x+\frac{1}{3}\right)-5.\left(x+\frac{1}{3}\right)=\frac{1}{2}.x\) \(x\)
<=> \(\left(x+\frac{1}{3}\right).\left(-2-5\right)=\frac{1}{2}.x\)
<=> \(\left(x+\frac{1}{3}\right).\left(-7\right)=\frac{1}{2}.x\)
<=> \(-7x-\frac{7}{3}=\frac{1}{2}.x\)
<=> \(-7x-\frac{1}{2}.x=\frac{7}{3}\)
<=> \(\left(-7-\frac{1}{2}\right).x=\frac{7}{3}\)
<=> \(\frac{-15}{2}.x=\frac{7}{3}\)
<=> \(x=\frac{7}{3}:\frac{-15}{2}=\frac{-14}{45}\)
\(-7x-\frac{7}{3}=\frac{1}{2}.x\)
<=> \(-7x-\frac{1}{2}x=\frac{7}{3}\)
<=> \(\left(-7-\frac{1}{2}\right).x=\frac{7}{3}\)
<=> \(\frac{-15}{2}.x=\frac{7}{3}\)
<=> \(x=\frac{7}{3}:\frac{-15}{2}=\frac{-14}{45}\)
\(|x|=x\)
\(x\in\left\{-x,x\right\}\)
\(|x|=-x\)
\(x\in\left\{\varnothing\right\}\)
\(|x+2|=x+2\)
\(x\in\left\{x\right\}\)
ko bt
\(|x+2|=x+2\)
\(\Leftrightarrow\orbr{\begin{cases}x+2=x+2\\x+2=-x-2\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}0=0\left(luondung\right)\\2x=-4\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x\in R\\x=-2\end{cases}}\)
tương tự phần tiếp
a, x.25=380125
x=380125:25
x=15205
b, (45,2+45.2)+2+x=2525255
45.2.2
45 . 2 + 2 + x + 45 . 2 = 2525255
=> 2 . (45 + 45 + 1) + x = 2525255
=> 182 + x = 2525255
=> x = 2525073