23.15 - [115 - (12 - 5) 2 ]
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a) = 8 . 15 - [115- 72 ]
= 8 . 15 - [115- 49 ]
= 120 - 56
= 64
b) = 100 : {250 : [450 - (2.125 - 8.25)]}
= 100 : {250 : [450 - (250 - 200 )]}
= 100 : {250 : [450 - 50]}
= 100 : {250 :400}
= 100 : 0,265
= 0,00265
=
\(a,2^3.15-\left[115-\left(12-5\right)^2\right]\)
\(=8.15-\left[115-\left(12-5\right)^2\right]\)
\(=120-\left[115-7^2\right]\)
\(=120-\left[115-49\right]\)
\(=120-66\)
\(=54\)
\(b,100:\left\{250:\left[450-\left(2.5^3-2^3.25\right)\right]\right\}\)
\(=100:\left\{250:\left[450-\left(2.125-8.25\right)\right]\right\}\)
\(=100:\left\{250:\left[450-\left(250-200\right)\right]\right\}\)
\(=100:\left\{250:\left[450-50\right]\right\}\)
\(=100:\left\{250:400\right\}\)
\(=100:0,625\)
\(=160\)
![](https://rs.olm.vn/images/avt/0.png?1311)
\(2^3.15-\left[115-\left(12-5\right)^2\right]=8.15-\left[115-7^2\right]=120-\left[115-49\right]=120-66=54\)
\(100:\left\{250:\left[450-\left(4.5^3-2^2.25\right)\right]\right\}=100:\left\{250:\left[450-\left(4.125-4.25\right)\right]\right\}=100:\left\{250:\left[450-\left(500-100\right)\right]\right\}\)
\(=100:\left[250:\left(450-400\right)\right]=100:\left(250:50\right)=100:5=20\)
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a) 23.15 -[115-(12-5)2 ]
= 23.15 -[115-36]
= 8.15 -79
= 120-79
=41
b)5.[(85 - 35 : 7) :8 + 90 ] - 50
=5 .[80:8+90]-50
=5.100-50
=500-50
=450
c){[261 - ( 36-31)3.2 ]-9}.1001
={[261 - 125.2 ]-9}.1001
={[261 -250 ]-9}.1001
={11-9}.1001
=2.1001
=2002
d)3.102 - [1200 - ( 42 - 2.3)3]
=3.100-[1200 -(16-6)3 ]
=300-[1200-1000]
=300-200
=100
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1 :
a) \(...=45\left(56+44\right)-500=45.100-500=4500-500=4000\)
b) \(...=3^2.6-6^{18}+1=45+1-6^{18}=46-6^{18}\)
c) \(...=756\left(66+48-14\right)=756.100=75600\)
d) \(...=8.15-\left(149-7^2\right)=120-\left(149-49\right)=120-100=20\)
Bài 2 :
a) \(x-21=46\Rightarrow x=21+46\Rightarrow x=87\)
b) \(2^x.4=128\Rightarrow2^x=32\Rightarrow2^x=2^5\Rightarrow x=5\)
c) \(3x+27=162\Rightarrow3x=162-27\Rightarrow3x=135\Rightarrow x=45\)
d) \(4x-8=4^{2023}.4^{2021}\)
\(\Rightarrow4x-8=4^{2023+2021}\)
\(\Rightarrow4x-8=4^{4044}\)
\(\Rightarrow4x=4^{4044}+8\)
\(\Rightarrow x=\left(4^{4044}+8\right):4\)
\(\Rightarrow x=4^{4043}+2\)
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