1. a) 6² : 4 . 3 + 2 . 5²
= 36 : 4 . 3 + 2 . 25
= 9 . 3 + 50
= 27 + 50
= 77
b) 5 . 4² - 32 : 4²
= 5 . 16 - 32 : 16
= 80 - 2
= 78
c) 80 - (4 . 5² - 3 .2³)
= 80 - (4 . 25 - 3 . 8)
= 80 - (100 - 24)
= 80 - 76
= 4
d) 2448 : [119 - (23 - 6)]
= 2448 : (119 - 17)
= 2448 : 102
= 24
e) 23 . 85 + 15 . 23 + 170
= 23 . (85 + 15) + 170
= 23 . 100 + 170
= 2300 + 170
= 2470
f) 3³ . 2 - 5 . 2023⁰ + 36 : 3²
= 27 . 2 - 5 . 1 + 36 : 9
= 54 - 5 + 4
= 53
2. a) 123 - 5.(x + 4) = 38
5.(x + 4) = 123 - 38
5.(x + 4) = 85
x + 4 = 85 : 5
x + 4 = 17
x = 17 - 4
x = 13
b) (3.x - 2⁴) . 7³ = 2 . 7⁴
3x - 16 = 2 . 7⁴ : 7³
3x - 16 = 2 . 7
3x = 14 + 16
3x = 30
x = 30 : 3
x = 10
c) (2600 + 6400) - 3.x = 1200
9000 - 3x = 1200
3x = 9000 - 1200
3x = 7800
x = 7800 : 3
x = 2600
d) [(6.x - 72) : 2 - 84] . 28 = 5628
(6x - 72) : 2 - 84 = 5628 : 28
(6x - 72) : 2 - 84 = 201
(6x - 72) : 2 = 201 + 84
(6x - 72) : 2 = 285
6x - 72 = 285 . 2
6x - 72 = 570
6x = 570 + 72
6x = 642
x = 642 : 6
x = 107
e) 70 - 5(x - 3) = 45
5(x - 3) = 70 - 45
5(x - 3) = 25
x - 3 = 25 : 5
x - 3 = 5
x = 5 + 3
x = 8
f) 10 + 2.x = 4⁷ : 4⁵
10 + 2x = 4²
10 + 2x = 16
2x = 16 - 10
2x = 6
x = 6 : 2
x = 3
g) 2.x - 138 = 2³.2²
2x - 138 = 2⁵
2x - 138 = 32
2x = 32 + 138
2x = 170
x = 170 : 2
x = 85
h) 231 - (x - 6) = 1339 : 13
231 - (x - 6) = 103
x - 6 = 231 - 103
x - 6 = 128
x = 128 + 6
x = 134
1.Tính:
a) \(6^2:4.3+2.5^2\)
\(=36:4.3+2.25\)
\(=9.3+50\)
\(=27+50\)
\(=77\)
b) \(5.4^2-32:4^2\)
\(=5.16-32:16\)
\(=80-2\)
\(=78\)
c) \(80-\left(4.5^2-3.2^3\right)\)
\(=80-\left(4.25-3.8\right)\)
\(=80-\left(100-24\right)\)
\(=80-76\)
\(=4\)
d) \(2448:\left[119-\left(23-6\right)\right]\)
\(=2448:\left[119-17\right]\)
\(=2448:102\)
\(=24\)
e) \(23.85+15.23+170\)
\(=23\left(85+15\right)+170\)
\(=23.100+170\)
\(=2300+170\)
\(=2470\)
f) \(3^3.2-5.2023^0+36:3^2\)
\(=27.2-5.1+36:9\)
\(=54-5+4\)
\(=53\)
2. Tìm x biết:
a) \(123-5.\left(x+4\right)=38\)
\(=>5.\left(x+4\right)=123-38\)
\(=>5.\left(x+4\right)=85\)
\(=>x+4=85:5\)
\(=>x+4=17\)
\(=>x=17-4\)
\(=>x=13\)
b) \(\left(3.x-2^4\right).7^3=2.7^4\)
\(=>3.x-2^4=2.7^4:7^3\)
\(=>3.x-2^4=2.7\)
\(=>3.x-16=14\)
\(=>3.x=14+16\)
\(=>3.x=30\)
\(=>x=30:3\)
\(=>x=10\)
c) \(\left(2600+6400\right)-3.x=1200\)
\(=>9000-3.x=1200\)
\(=>3.x=9000-1200\)
\(=>3.x=7800\)
\(=>x=7800:3\)
\(=>x=2600\)
d) \(\left[\left(6.x-72\right):2-84\right].28=5628\)
\(=>\left(6.x-72\right):2-84=5628:28\)
\(=>\left(6.x-72\right):2-84=201\)
\(=>\left(6.x-72\right):2=201+84\)
\(=>\left(6.x-72\right):2=285\)
\(=>6.x-72=285\times2\)
\(=>6.x-72=570\)
\(=>6.x=570+72\)
\(=>6.x=642\)
\(=>x=642:6\)
\(=>x=107\)
e) \(70-5.\left(x-3\right)=45\)
\(=>5.\left(x-3\right)=70-45\)
\(=>5.\left(x-3\right)=25\)
\(=>x-3=25:5\)
\(=>x-3=5\)
\(=>x=5+3\)
\(=>x=8\)
f) \(10+2.x=4^7:4^5\)
\(=>10+2.x=4^2\)
\(=>10+2.x=16\)
\(=>2.x=16-10\)
\(=>2.x=6\)
\(=>x=6:2\)
\(=>x=3\)
g) \(2.x-138=2^3.3^2\)
\(=>2.x-138=8.9\)
\(=>2.x-138=72\)
\(=>2.x=72+138\)
\(=>2.x=210\)
\(=>x=210:2\)
\(=>x=105\)
h) \(231-\left(x-6\right)=1339:13\)
\(=>231-\left(x-6\right)=103\)
\(=>x-6=231-103\)
\(=>x-6=128\)
\(=>x=128+6\)
\(=>x=134\)
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