Question

Bài 2: Tìm x thuộc Z biết:

a. x = \(2^4+3^2.3^2\)                                           b. 71+ (26-3x) :5 = 75                               c. 4 - (27-3) = x - (13-4)         

Answer 1

a) x= \(2^4+3^2.3^2=2^4+3^4=16+81=97\)

b) 71+(26-3x):5=75

<=> (26-3x):5=75-71=4

<=> 26-3x=4.5=20

<=> 3x=26-20=6

<=> x=2

c)4-(27-3)=x-(13-4)

<=> 4-24=x-9

<=>x=4-24+9=-11

Answer 2

a) x = 2⁴ + 3² . 3²

=> x = 2⁴ + 3⁴

=> x = 16 + 81

=> x = 97

Vậy x = 97

b) 71 + ( 26 - 3x ) : 5 = 75

=> ( 26 - 3x ) : 5 = 75 - 71

=> ( 26 - 3x ) : 5 = 4

=> 26 - 3x = 4 . 5

=> 26 - 3x = 20

=> 3x = 26 - 20

=> 3x = 6

=> x = 6 : 3

=> x = 2

Vậy x = 2

c) 4 - ( 27 - 3 ) = x - ( 13 - 4 )

=> 4 - 24 = x - 9

=> - 20 = x - 9

=> x = (- 20 ) + 9

=> x = - 11

Vậy x = -11