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\(15.x< 750\)
\(x=750:15\)
\(x=50\)
Vậy x bằng các số nhỏ hơn 50.
\(3.\left(x-12\right)=36\)
\(x-12=36:3\)
\(x-12=12\)
\(x=12+12\)
\(x=24\)
\(\left(x+251\right)-301=56\)
\(x-251=56+301\)
\(x-251=357\)
\(x=357+251\)
\(x=608\)
\(152+\left(x+231\right):2=358\)
\(\left(x+231\right):2=358-152\)
\(\left(x+231\right):2=206\)
\(x+231=206.2\)
\(x+231=412\)
\(x=412-231\)
\(x=181\)
k nhé mình nhanh
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a) `537 + (56 + 216) - (216 + 437)=537+56+216-216-437=(537-437)+(216-216)+56=100+0+56=156`
b) `271 - (- 43) + 271 + (- 17)=271+43+271-17=568`
c) `26 . (- 125) - 125 (- 36)= (-26) .125- 125 (- 36)=125[(-26)-(-36)]=125.10=1250`
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a ) | x | − 3 4 = 5 3 = > | x | = 29 12 = > x = 29 12 x = − 29 12
b) x − 3 2 = 1 = > x − 3 2 = 1 x − 3 2 = − 1 = > x = 5 2 x = 1 2
c) x − 3 2 + 11 4 = 15 4 = > x − 3 2 = 1 = > x = 5 2 x = 1 2
d) 17 4 − 5 6 − x = − 7 4 = > 5 6 − x = 6 = > x = − 31 6 x = 41 6
e)
x + 1 5 2 − 9 25 = 0 = > x + 1 5 2 = 9 25 = > x + 1 5 = 3 5 x + 1 5 = − 3 5 = > x = 2 5 x = − 4 5
f) x + 1 5 2 + 17 25 = 26 25 = > x + 1 5 2 = 9 25 = > x = 2 5 x = − 4 5
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Bài 1:
hình như A bn chép sai đề.mk nghĩ 216 phải là 217 . mk giải luôn nhé !!!!!
A=42+49+56+....+217
A=7.6+7.7+7.8+...+7.31
A=7.(6+7+8+..+31)
A=7.462
A=3234
B=42+49+56+...+154
B=7.6+7.7+7.8+....+7.22
B=7.(6+7+8+...+22)
B=7.224
B=1792
BÀI 2 LẦM SAU MK SẼ LÀM, MUỘN RỒI !XIN LỖI NHA BN @!!!!!!!
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\(B=\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}+\frac{1}{143}\)
\(=\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}+\frac{1}{11\cdot13}\)
\(=\frac{1}{2}\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}+\frac{1}{11}-\frac{1}{13}\right)\)
\(=\frac{1}{2}\left(\frac{1}{3}-\frac{1}{13}\right)=\frac{5}{39}\)
152-216=-94
56-6523=-6467
-64
-6467
đúng ko
k mk nha