Question

Tìm x thuộc N,sao cho

7^x- 3.7²³=4.7²³

2.5^x+1+3.5²¹=5²²

Answer 1

a)7^x-3.7²³=4.7²³

7^x           =4.7²³+3.7²³

7^x           =7²³.(4+3)

7^x           =7²³.7

7^x           = 7²⁴

=> x = 24

b)2.5^x+1+3.5²¹=5²²

2.5^x+1            = 5²²-3.5²¹

2.5^x+1            = 5²¹(5-3)

2.5^x+1            =5²¹.2

=>5^x+1 = 5²¹

=>x+1 = 21

 x       = 21 - 1

 x       = 20

Answer 2

a. 7\(^x\)- 3.27^23 = 4.7^23

7^x = 7.7^23

7^x = 7^24

x = 24

b.