Question

[gấu bông]

bài 1: tìm số chưa biết x  thuộc N

1/60-3.(x-2)=51

2/ 3.(x-36): 18 = 12

3/ (x-3)³ = 27

4/ 2^x- 15 = 17

5/  ( 3x - 2⁴) .7³=2.7⁴

6/ [( 6x - 39) : 3].28=5628

7/( 3x - 15)² - 6 = 75

8/ 128 - 3 . (x +4)=23

9/ (12x -4³ ).8³=4.8⁴

10/ 720: [41- (2x - 5)]= 2³ . 5

Answer 1

[Ngọc Vĩ]

1/ 3(x - 2) = 9 => x - 2 = 3 => x = 5

2/ 3(x - 36) = 216 => x - 36 = 72 => x = 108

3/ (x - 3)³ = 3³ => x - 3 = 3 => x = 6

4/ 2^x = 32 => 2^x = 2⁵ => x = 5

5/ 3x - 16 = 2.7⁴ : 7³ = 14 => 3x = 30 => x = 10

6/ (6x - 39) : 3 = 201 => 6x - 39 = 603 => 6x = 642 => x = 107

7/ (3x - 15)² = 81 => (3x - 15)² = 9² => 3x - 15 = 9 => 3x = 24 => x = 8

8/ 3(x + 4) = 105 => x + 4 = 35 => x = 31

9/ 12x - 4³ = 4.8⁴ : 8³ = 32 => 12x = 32 : 64 => 12x = 1/2 => x = 1/24

10/ 41 - (2x - 5) = 680 => 2x - 5 = -639 => 2x = -634 => x = - 317