Kiu tui ..........

Đáp án+Giải thích các bước giải:

Bài 4 :

a) 10 + 2x = $4^{7}$ ÷ $4^{5}$

10 + 2x = $4^{7-5}$

10 + 2x = $4^{2}$

10 + 2x = 16

2x = 16 - 10

2x = 6

x = 6 ÷ 2

x = 3

b) 210 ÷ x - 5 = 25

210 ÷ x = 25 + 5

210 ÷ x = 30

x = 210 ÷ 30

x = 7

c) 130 - ( 75 - x ) = 25

75 - x = 130 - 25

75 - x = 105

x = 75 - 105

x = -30

e) 131 - 3( x + 4 ) = 23

3( x + 4 ) = 131 - 23

3( x + 4 ) = 108

x + 4 = 108 ÷ 3

x + 4 = 36

x = 36 - 4

x = 32

g) 36 ÷ ( x - 5 ) = 3²

36 ÷ ( x - 5 ) = 9

x - 5 = 36 ÷ 9

x - 5 = 4

x = 4 + 5

x = 9

h) ( 2x + 1 ) ÷ 7 = $2^{4}$ + 3²

( 2x + 1 ) ÷ 7 = 16 + 9

( 2x + 1 ) ÷ 7 = 25

2x + 1 = 25 × 7

2x + 1 = 175

2x = 175 - 1

2x = 174

x = 174 ÷ 2

x = 87 

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