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c: =>x+2>0
hay x>-2
d: =>-4<=x<=3
e: =>\(x\in\varnothing\)
f: \(\Leftrightarrow\left[{}\begin{matrix}x>4\\x< -6\end{matrix}\right.\)
\(a,\Leftrightarrow\dfrac{\left(n+15\right)\left(15-n+1\right)}{2}=0\\ \Leftrightarrow\left[{}\begin{matrix}n=-15\\n=14\left(l\right)\end{matrix}\right.\Leftrightarrow n=-15\\ b,\Leftrightarrow\dfrac{\left(35+n\right)\left(35-n+1\right)}{2}=0\\ \Leftrightarrow\left[{}\begin{matrix}n=-35\left(n\right)\\n=34\left(l\right)\end{matrix}\right.\Leftrightarrow n=-35\)
a,3.52+(15.22-23.22)
= 156 + 22(15 - 23)
= 156 + 22. (-8)
= 156 - 176
= -20
b,75.34+76.75-75.10
= 75(34 + 76 - 10)
= 75. 100
= 7500
c,84:4+3 mũ 9 : 3 mũ 7 +2017 mũ 0
= 84 : 4 + 39 : 37 + 20170
= 21 + 9 + 1
= 31
a) Ta có: \(3\cdot52+\left(15\cdot22-23\cdot22\right)\)
\(=3\cdot52+22\cdot\left(15-23\right)\)
\(=3\cdot52+22\cdot\left(-8\right)\)
\(=156-176=-20\)
b) Ta có: \(75\cdot34+76\cdot75-75\cdot10\)
\(=75\cdot\left(34+76-10\right)\)
\(=75\cdot\left(110-10\right)\)
\(=75\cdot100\)
\(=7500\)
c) Ta có: \(84:4+3^9:3^7+2017^0\)
\(=21+3^{9-7}+1\)
\(=22+3^2\)
\(=22+9=31\)
Ta có :
\(B=4+2^2+2^3+2^4+...+2^{2016}\)
\(\Rightarrow\) \(B-4=2^2+2^3+2^4+...+2^{2016}\)
\(\Rightarrow\) \(2\left(B-4\right)=2^3+2^4+2^5+...+2^{2017}\)
\(\Rightarrow\) \(2\left(B-4\right)-\left(B-4\right)=B-4=2^{2017}-2^2\)
\(\Rightarrow\) \(B=2^{2017}-2^2+4=2^{2017}\)
\(\Rightarrow\) \(A=B=2^{2017}\)
Vậy \(A=B\)
\(A=\frac{\left[\left(25-1\right):1+1\right]\left(25+1\right)}{2}=325.\)
\(B=\frac{\left[\left(51-3\right):2+1\right]\left(51+3\right)}{2}=675\)
\(C=\frac{\left[\left(81-1\right):4+1\right]\left(81+1\right)}{2}=861\)
a, 315 + (146 - x) = 401
146 - x = 401 - 315
146 - x = 86
x = 146 - 86
x = 60
a: \(315+\left(146-x\right)=401\)
\(\Leftrightarrow146-x=86\)
hay x=60
b: \(x+251-301=56\)
\(\Leftrightarrow x+251=357\)
hay x=106
\(35\cdot34+35\cdot86+65\cdot75+65\cdot45\)
\(=35\left(34+86\right)+65\left(75+45\right)\)
\(=35\cdot120+65\cdot120\)
\(=120\left(35+65\right)\)
\(=120\cdot100\)
\(=12000\)
35.34+35.86+65.75+65.45=1190+3010+4875+2925
=4200+7800
=12000
<=> 15 - ( - 5 )2 - 25
<=> 15 - ( 25 + 25 )
=> 15 - 50 = - 35
A)9-25=(7-x)-(25-7)
9-25=7-x-25-7
9-25=(7-7)-(x+25)
9-25=0-x-25
9-25=x-25
25+25=9+x
50=9+x
x=50-9
x=41