Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
1,
a,\(2020-\left(249+2020\right)+\left(249-573\right)\)
\(=2020-249-2020+249-573\)
\(=-573\)
b,\(\left|-257\right|+\left(-3\right)^0-\left(18+257\right)\)
\(=257+1-18-257\)
\(=1-18=-17\)
\(c,25.\left(85-47\right)-85.\left(47+25\right)\)
\(=25.85-25.47-47.85+85.25\)
\(=85.\left(25-47+25\right)-25.47\)
\(=85.3-25.47\)
\(=-920\)
2,
\(a,15-5.\left(x+2\right)=-30\)
\(=>5.\left(x+2\right)=15+30=45\)
\(=>x+2=\frac{45}{5}=9\)
\(=>x=7\)
\(b,\left(x+2\right)^2+5=105\)
\(=>\left(x+2\right)^2=100\)
\(=>\left(x+2\right)^2=10^2\)
\(=>x+2=10\)
\(=>x=8\)
\(c,\left|2x-5\right|-\left(-6\right)=11\)
\(=>\left|2x-5\right|=11-6=5\)
\(=>\orbr{\begin{cases}2x-5=5\\2x-5=-5\end{cases}}\)
\(=>\orbr{\begin{cases}2x=5-5=0\\2x=-5+5=0\end{cases}=>x=0}\)
a, \(\left(2x-4\right).\left(x+3\right)=0\)
\(TH1:2x-4=0\)
\(2x=4+0\)
\(2x=4\)
\(x=4:2\)
\(x=2\)
\(TH2:x+3=0\)
\(x=0+3\)
\(x=3\)
Vậy \(x\in\left\{2;3\right\}\)
a) 10-x-5=-5-7-11
=> 5 - x = -23
=> x = 28
b) |x| -3=0
=> |x| = 3
=> x = 3 hoặc x -3
c) ( 7-|x| ) .(2x-4)=0
=> 7 - |x| = 0 hoặc 2x - 4 = 0
=> |x| = 7 hoặc 2x = 4
=> x = 7 hoặc x = - 7 hoặc x = 2
c)2+3x=-15-19
=> 2 + 3x = -34
=> 3x = 36
=> x = 12
a/ \(7x-18=-81\)
\(\Leftrightarrow7x=-81+18\)
\(\Leftrightarrow7x=-63\)
\(\Leftrightarrow x=-63:7\)
\(\Leftrightarrow x=-8\)
Vậy .....
b/ \(3-\left|2x+5\right|=-4\)
\(\Leftrightarrow\left|2x-5\right|=3-\left(-4\right)\)
\(\Leftrightarrow\left|2x-5\right|=7\)
\(\Leftrightarrow\left[{}\begin{matrix}2x-5=7\\2x-5=-7\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=12\\2x=-2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=-1\end{matrix}\right.\)
Vậy ....
c/ \(\left|x-3\right|=0\)
\(\Leftrightarrow x-3=0\)
\(\Leftrightarrow x=3\)
Vậy ....
d/ \(x-5⋮3x+2\)
Mà \(3x+2⋮3x+2\)
\(\Leftrightarrow\left\{{}\begin{matrix}3x-15⋮3x+2\\3x+2⋮3x+2\end{matrix}\right.\)
\(\Leftrightarrow17⋮3x+2\)
\(\Leftrightarrow3x+2\inƯ\left(17\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}3x+2=1\\3x+2=17\\3x+2=-1\\3x+2=-17\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{3}\\x=5\\x=-1\\x=-\dfrac{19}{3}\end{matrix}\right.\)
Vậy ...
bạn người ta quy định là ra số nguyên mà câu d sai rồi