A,(12x-4^3)×8^3=4×8^7 B,(x+1)3=8 C,(21-3)^3=-27 các bạn nhanh giúp mình nhé
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\(b,\left(x+1\right)\times3=8\)
\(\Leftrightarrow x+1=\frac{8}{3}\)
\(\Leftrightarrow x=\frac{8}{3}-1\)
\(\Leftrightarrow x=\frac{5}{3}\)
\(c,\left(21-3\right)^3=-27\)
\(\Leftrightarrow\left(21-3\right)^3=\left(-3\right)^3\)
\(\Leftrightarrow21-3=-3\)\(???\)ĐỀ SAI RỒI BẠN
\(a,\left[12\times\left(-4^3\right)\right]\times8^3=4\times\frac{8}{7}\)
\(\left[12\times\left(-64\right)\right]\times512=\frac{32}{7}\)
\(-768\times512=\frac{32}{7}\)\(???\)ĐỀ SAI RỒI BẠN
a) 1/2 + 3/4 - (3/4 - 4 - 5)
= 1/2 + 3/4 - 3/4 + 4 + 5
= (3/4 - 3/4) + (4 + 5) + 1/2
= 0 + 9 + 1/2
= 19/2
b) [9/16 + 8/(-27)] - (19/27- 7/16 - 2)
= 9/16 - 8/27 - 19/27 + 7/16 + 2
= (9/16 + 7/16) + (-8/27 - 19/27) + 2
= 1 - 1 + 2
= 2
c) -5/8 . [4/9 + 7/(-12)]
= -5/8 . (-5/36)
= 25/288
d) 7/10 . (-3/5) + 7/10 . (-2/5) - (-3/10)
= 7/10 . (-3/5 - 2/5) + 3/10
= 7/10 . (-1) + 3/10
= -2/5
e) -3/7 . 5/9 + 4/9 . (-3/7) + 2 3/7
= -3/7 . (5/9 + 4/9) + 17/7
= -3/7 . 1 + 17/7
= 2
f) 8 2/7 - (3 4/9 + 4 2/7)
= 8 + 2/7 - 3 - 4/9 - 4 - 2/7
= (8 - 3 - 4) + (2/7 - 2/7) - 4/9
= 1 - 4/9
= 5/9
h) 3.(-1/2)² - (4/5 + 8/15) : 5/6
= 3.1/4 - 4/3 : 5/6
= 3/4 - 8/5
= -17/20
A,-3/-7+5/19+-4/7
=(-3/-7+-4/7)+5/19
=-1/7+5/19=16/133
B,-13/24+-5/24+7/21
=-3/4+7/21=-5/12
C,-5/13+(-8/13+1)
=(-5/13+-8/13)+1
=-1+1=0
D,2/3+(3/8+-2/3)
=(2/3+-2/3)+3/8
=0+3/8=3/8
E,(-3/4+5/8)+-1/8
=-1/8+1/8=0
a)
=(x-2)3
b)\(\left(2-x\right)^3\)
c)\(\left(x+\dfrac{1}{3}\right)^3\)
d)\(\left(\dfrac{x}{2}+y\right)^3\)
e)
\(=\left(x-1\right)^2\left(x-1-15\right)+25\left[3\left(x-1\right)-5\right]\)
\(=\left(x-1\right)^2\left(x-16\right)+25\left(3x-3-5\right)\)
\(=\left(x-1\right)^2\left(x-16\right)+25\left(3x-8\right)\)
\(a)5\frac{3}{5}+1\frac{3}{4}+4\frac{1}{4}+3\frac{2}{5}\)
\(=\)\((5\frac{3}{5}+3\frac{2}{5})+(1\frac{3}{4}+4\frac{1}{4})\)
\(=[8+(\frac{3}{5}+\frac{2}{5})]+[5+(\frac{3}{4}+\frac{1}{4})]\)
\(=(8+1)+(5+1)\)
\(=9+6=15\)
\(b)\frac{75}{100}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=\frac{3}{4}+\frac{18}{21}+\frac{19}{32}+\frac{1}{4}+\frac{3}{21}+\frac{13}{32}\)
\(=(\frac{3}{4}+\frac{1}{4})+(\frac{18}{21}+\frac{3}{21})+(\frac{19}{32}+\frac{13}{32})\)
\(=1+1+1=3\)
_Học tốt_
a/ 128 . 3 . (x + 4) = 23
=> 384. (x + 4) = 23
=> x + 4 = 23/384
=> x = -1513/384
b/ 100 - 7 .(x + 5) = 58
=> 7. (x + 5) = 42
=> x + 5 = 6
=> x = 1
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