Question

[Sakura]

tĩm

a) (2x+1)²=25

b) (x-1)³=-125

c) 2^x+2-2^x=96

d) 7^x+2+2.7^x-1=345

Answer 1

[uzumaki naruto]

 a) (2x+1)²=25

 (2x+1)²= (+-5)²

=> 2x+1 = 5 hoặc 2x + 1 = -5

2x = 4 hoặc 2x = -6

x= 2 hoặc x=-3

b) (x-1)³=-125

(x-1)³= (-5)³

=> x-1 = -5 

x= -4

c) 2^x+2-2^x=96

2^x.2^{2 -} 2^x = 96

2^x( 4-1) = 96

2^x = 96 : 3

2^x= 32

2^x = 2⁵

=> x= 5

Answer 2

[uzumaki naruto]

d) 7^x+2+2.7^x-1=345

7^x-1 . 7³ +  2.7^x-1=345

7^x-1( 7³ +2) = 345

7^x-1 . 345 = 345

7^x-1 =1

=> x-1 = 0

=> x= 1