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a,\(2,5.16,27.4+7,3=16,27.10+7,3=162,7+7,3=170\)
b,\(8.6.10+4.25.12+3.16.31+2.34.24=48.10+48.25+48.31+48.34\)
\(=48.\left(10+25+31+34\right)=48.100=4800\)
c,\(78.31+78.24+78.17+22.72=78\left(31+24+17\right)+22.72=78.72+22.72\)
\(=72.\left(78+22\right)=72.100=7200\)
d,\(102.67-34.51=102.67-17.102=102.\left(67-17\right)=102.50=5100\)
đéo hiểu thì cút nhé đéo ai khiến m trả lời cả . ngu thì nói ngu đi đừng bày đặt t ghét nhất là cái loại như m đấy ạ
Bài 2
a, \(1-\left(12,5+x-4,25\right):21,75=0\)
\(=>21,75-12,5-x+4,25=0\)
\(=>13,5-x=0=>x=13,5\)
b,\(x.101-x+72.99+72=21050\)
\(=>100x+72.100=21050\)
\(=>100\left(x+72\right)=21050\)
\(=>x+72=210,5\)\(=>x=138,5\)
c,\(151-2\left(x-6\right)=2227:17\)
\(=>151-2\left(x-6\right)=131\)
\(=>2\left(x-6\right)=20\)
\(=>2x=32=>x=16\)
d,\(\left(x+4\right)+\left(x+6\right)+\left(x+8\right)+...+\left(x+26\right)=210\)\(=>12x+\left(4+6+8+...+26\right)=210\)
\(=>12x+180=210=>12x=30\)
\(=>x=\frac{30}{12}=\frac{15}{6}=\frac{5}{2}\)
a/ \(3x+2xy=7\)
\(\Leftrightarrow x\left(2y+3\right)=7\)
\(\Leftrightarrow x;2y+3\inƯ\left(7\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\2y+3=7\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\2y+3=-7\end{matrix}\right.\\\left\{{}\begin{matrix}x=7\\2y+3=1\end{matrix}\right.\\\left\{{}\begin{matrix}x=-7\\2y+3=-1\end{matrix}\right.\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y=2\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\y=-5\end{matrix}\right.\\\left\{{}\begin{matrix}x=7\\y=-\dfrac{3}{2}\end{matrix}\right.\\\left\{{}\begin{matrix}x=-7\\y=-2\end{matrix}\right.\end{matrix}\right.\)
Vậy ...
b/ \(3x-5xy=11\)
\(\Leftrightarrow x\left(3-5y\right)\inƯ\left(11\right)\)
\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\3-5y=11\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\3-5y=-11\end{matrix}\right.\\\left\{{}\begin{matrix}x=11\\3-5y=1\end{matrix}\right.\\\left\{{}\begin{matrix}x=-11\\3-5y=-1\end{matrix}\right.\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x=1\\y=-\dfrac{8}{5}\end{matrix}\right.\\\left\{{}\begin{matrix}x=-1\\y=\dfrac{14}{5}\end{matrix}\right.\\\left\{{}\begin{matrix}x=7\\y=\dfrac{2}{5}\end{matrix}\right.\\\left\{{}\begin{matrix}x=-7\\y=-\dfrac{4}{5}\end{matrix}\right.\end{matrix}\right.\)
Vậy ...
Bài 2:
a)|x| < 3
x\(\in\){-2;-1;0;1;2}
b)|x - 4 | < 3
x\(\in\){ 6 ; 5 ; 4 ; 3 ; 2 }
c) | x + 10 | < 2
x\(\in\){ -2 ; -10 }
Bài 1:
A = 1 + 2 - 3 + 4 + 5 - 6 +...+98 - 99
A = (1 + 4 + 7 +...+97) + [(2-3)+(5-6)+...+(98-99)]
A = 1617 + [(-1)+(-1)+...+(-1)]
A = 1617 + (-49)
A = +(1617-49) = A = 1568
B = - 2 - 4 + 6 - 8 + 10 + 12 - .... + 60
B =
2)
a) \(x\in\left\{2;1;0;-1;-2\right\}\)
b) \(x\in\left\{6;-6;5;-5;4\right\}\)
c) \(x\in\left\{-9;-11;-10\right\}\)
3)
\(\left(a;b\right)\in\left\{\left(0;1\right);\left(0;-1\right);\left(1;0\right);\left(-1;0\right)\right\}\)
1) (-37) + 14 + 26 + 37
= [(-37) + 37] + 14 + 26
= 0 + 40
= 40
2) (-24) + 6 + 10 + 24
= [(-24) + 24] + 6 + 10
= 0 + 16
= 16
3) 15 + 23 + (-25) + (-23)
= 15 + (-25) + [(-23) + 23]
= -10 + 0
= -10
4) 60 + 33 + (-50) + (-33)
= 60 + (-50) + [(-33) + 33]
= 10 + 0
= 10
Trả lời:
a, ( - x + 5 )2 - 16 = ( - 22 ) . 5
=> ( - x + 5 )2 - 16 = - 20
=> ( - x + 5 )2 = - 20 + 16
=> ( - x + 5 )2 = - 4 ( vô lí )
Vậy không tìm được x thỏa mãn đề bài.
b, 50 - ( 20 - x ) = - x - ( 45 - 85 )
=> 50 - 20 + x = - x - ( - 40 )
=> 30 + x = - x + 40
=> x + x = 40 - 30
=> 2x = 10
=> x = 10 : 2
=> x = 5
Vậy x = 5
(10^2+11^2+12^2) : (13^2+14^2)
=[(12+1)^2+(12+2)^2] : (13^2+14^2)
=(13^2+14^2) : (13^2+14^2)
=1
`Answer:`
\(12x-144=0\)
\(\Leftrightarrow12x=144\)
\(\Leftrightarrow x=144:12\)
\(\Leftrightarrow x=12\)
\(5x-32:18=13\)
\(\Leftrightarrow5x-\frac{16}{9}=13\)
\(\Leftrightarrow5x=13+\frac{16}{9}\)
\(\Leftrightarrow5x=\frac{133}{9}\)
\(\Leftrightarrow x=\frac{133}{9}:5\)
\(\Leftrightarrow x=\frac{133}{45}\)
\(3x+6=15\)
\(\Leftrightarrow3x=9\)
\(\Leftrightarrow x=3\)
45 - 5. ( 12 + 9) = 45 - 5 . ( 10 + 11 )
= 45 - 50 - 55
= -5 -55 = - 60
cho mk nhé ! tks
45 - 5 . ( 12 + 9 )
=45 - (5 . 9 + 5 . 12)
= 45 - ( 45 + 60)
= 45 - 45 - 60
= 0 - 60
= - 60
A = 10 + 11 + 12 + 13 +.....+ 99
A = (10 + 99) x { (99-10):1+1}: 2
A = 4905
số số hạng : ( 99 - 11 ) : 1 + 1 = 89
Tổng: ( 99 + 11 ) x 89 : 2 = 4895