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64 x y - y x 13 -y = 43
y x (64-13-1)=43
y x 50 =43
y=43:50
y=43/50
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mình trả lời ý a
64 x 25 +35 x 25 +25 x 1
= 25 x ( 64 + 35 + 1 )
= 25 x 100
= 2500
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a, (85 + 15) x y = 4000 c,
100 x y = 4000
y = 4000 : 10
y = 40
b; 18 + y + y + y = 48 x 25
18 + (y + y + y) = 1200
18 + 3y = 1200
3y = 1200 - 18
3y = 1182
y = 1182 : 3
y = 394
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43 x 27 + 93 x 43 + 57 x 61 + 59 x 57
= 43 x ( 27 + 93 ) + 57 x ( 61 + 59 )
= 43 x 120 + 57 x 120
= 120 x ( 43 + 57 )
= 120 x 100
= 1200
b) 64 x 6 + 81 x 4 + 17 x 6
= 6 x ( 64 + 17 ) + 81 x 4
= 6 x 81 + 81 x 4
= 81 x ( 6 + 4 )
= 81 x 10
= 810
A) =43 x (27+93)+57*(61+59)
=43*120+57*120
=120*(43+57)
=120*100
=12000
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a. 64 x 25 + 35 x 25 + 25
= 64 x 25 + 35 x 25 + 25 x 1
= 25 x ( 64 + 35 + 1 )
= 25 x 100
= 2500
b. 58 x 42 + 32 x 8 + 5 x 16
c. ( 42 x 43 + 57 x 43 + 43 ) - 360 : 4
= 42 x 43 + 57 x 43 + 43 x 1 - 90
= 43 x ( 42 + 57 +1 ) - 90
= 43 x 100 - 90
= 4300 - 90
= 4210
d. 456 : 2 x 181456 : 3 - 102
Trả lời:
a,\(64\times25+35\times25+25\)
\(=25\times\left(64+35+1\right)\)
\(=25\times100\)
\(=2500\)
b,\(58\times42+32\times8+5\times16\)
\(=2436+256+80\)
\(=2772\)
c,\(\left(42\times43+57\times43+43\right)-360\div4\)
\(=43\times\left(42+57+1\right)-90\)
\(=43\times100-90\)
\(=4300-90\)
\(=4210\)
d,\(456\div2\times181456\div3-102\)
\(=228\div3\times181456-102\)
\(=76\times181456-102\)
\(=13790656-102\)
\(=13790554\)
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\(\frac{5}{1.2}+\frac{5}{2.3}+\frac{5}{3.4}+...+\frac{5}{x\left(x+1\right)}=\frac{64}{13}\)
\(\Leftrightarrow5\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{x}-\frac{1}{x+1}\right)=\frac{64}{13}\)
\(\Leftrightarrow1-\frac{1}{x+1}=\frac{64}{13}\div5\)
\(\Leftrightarrow1-\frac{1}{x+1}=\frac{64}{65}\)
\(\Leftrightarrow\frac{1}{x+1}=1-\frac{64}{65}\)
\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{65}\)
\(\Rightarrow x+1=65\Rightarrow x=65-1=64\)
\(\text{Vậy }x=64\)
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a) 43 x 27 + 43 x 13 + 43 x 68
= 43 x ( 27 + 13 + 68 )
= 43 x 108
= 43 x ( 100 + 8 )
= 43 x 100 + 43 x 8
= 4300 + 344
= 4644
b) 90 x 21 + 15 x 10 + 30 x 74
= 30 x 63 + 30 x 5 + 30 x 74
= 30 x ( 63 + 5 + 74 )
= 30 x 142
= 30 x ( 100 + 42 )
= 30 x 100 + 30 x 42
= 3000 + 1260
= 4260
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phép tính này có quy tắc :
nhân chia trước, cộng trừ sau.
trong ngoặc trc ngoài ngoặc sau
tíc mình nha
(42 x 43 + 43 x 57 + 43) - 360 : 4
= 4426549 - 360 : 4
= 4426549 - 90
= 4426459
(372 - 19 x 4 + (981 : 9 - 13)
= 296 + 96
= 392
456 : 2 x 18 + 456 : 3 - 102
= 4104 + 50
= 4154
>_< học tốt
64 . x - 13 . x - x = 43
x . (64 - 13 - 1 ) = 43
x . 50 = 43
x = 43 : 50
x = \(\frac{43}{50}.\)