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a) 35- {12 - [(-14)+(-2)] }
=35 - [12-(-14-2)]
=35-[12-16]
=35-(-4)
=35+4
=39
b) 49 - (- 54) - 23
=49 + 54 - 23
= 80
c) |31 - 17 | - |13 - 52|
= |14| - | -39|
=14-39
= -25
d) -|-5|+ (-19) + 18 +|11-4| - 57
=-5 - 19 + 18 + 7 - 57
= -5-1-50
=-56
e) 126 + (-20) + |124| - (- 320) - |- 150|
= 126 - 20 + 124 + 320 - 150
= 400
g) (- 17) + 5 +8 +17 + (-3)
=(-17+17)+(5+8-3)=10
h) [( -15) + ( - 21 )] - ( 25 -15 - 35- 21)
=-15-21-25+15+35+21
=(-15+15)+(21-21)+(35+15-25)
=25
=-4 - 46
= -50 Tick cho mik nha
A = \(\frac{-5x}{21}\)+ \(\frac{-5y}{21}\)+ \(\frac{-5x}{21}\)
= \(\frac{\left(-5x\right)+\left(-5y\right)+\left(-5x\right)}{21}\)
vì x + y là số dõi của z
=> x + y + z = 0
=> \(\frac{5.\left(x+y+z\right)}{21}\)
= \(\frac{-5}{21}\). 0 = 0
=> A = 0
hok tốt !
Thay -z=x+y vào biểu thức A ta có A=-5x/21+(-5y/21)+[5(x+y)/21] =>-5x/21 +(-5y/21)+(5x+5y)/21=>-5x/21+(-5y/21)+5x/21+5y/21 => A = 0
Theo đầu bài ta có:
\(A=\frac{-5x}{21}+\frac{-5y}{21}+\frac{-5z}{21}\)
\(=\frac{-5x+-5y+-5z}{21}\)
\(=\frac{-5\left(x+y+z\right)}{21}\)
\(=\frac{-5\left(-z+z\right)}{21}\)
\(=\frac{-5\cdot0}{21}\)
\(=\frac{0}{21}=0\)
\(A=\frac{-5x}{21}+\frac{-5y}{21}+\frac{-5z}{21}\)
=>\(A=\frac{\left(-5x\right)+\left(-5y\right)+\left(-5z\right)}{21}\)
=>\(A=\frac{\left(-5\right)\left(x+y+z\right)}{21}\)
=>\(A=\frac{\left(-5\right)\left(-z+z\right)}{21}\)
=>\(A=\frac{\left(-5\right).0}{21}\)
=>\(A=\frac{0}{21}\)
=>A=0
\(\frac{17}{21}\cdot\frac{48}{53}+\frac{17}{21}\cdot\frac{4}{53}+\frac{52}{53}\cdot\frac{4}{21}\)
\(=\frac{17}{21}\left(\frac{48}{53}+\frac{4}{53}\right)+\frac{52}{53}\cdot\frac{4}{21}\)
\(=\frac{17}{21}\cdot\frac{52}{53}+\frac{52}{53}\cdot\frac{4}{21}\)
\(=\frac{52}{53}\left(\frac{17}{21}+\frac{4}{21}\right)\)
\(=\frac{52}{53}\cdot1\)
\(\frac{17}{21}.\frac{48}{53}+\frac{17}{21}.\frac{4}{53}+\frac{52}{53}.\frac{4}{21}\)
= \(\frac{17}{21}.\left(\frac{48}{53}+\frac{4}{53}\right)+\frac{52}{53}.\frac{4}{21}\)
= \(\frac{17}{21}.\frac{52}{53}+\frac{52}{53}.\frac{4}{21}\)
=\(\frac{52}{53}.\left(\frac{17}{21}+\frac{4}{21}\right)\)
= \(\frac{52}{53}\)
ai choi free fire ket bn ik