Question

bài 1 tìm x

a, 230 + [ 2⁴ + ( x - 5 ) ] = 315 . 2020⁰

b, 707 : [ ( 2^x - 5 ) + 74 ] = 4² - 3²

c, [ ( 6x - 12 ) : 3 ] . 32 = 64 

d , ( x : 7 + 15 ) . 23 + 391

e , ( 19 . x + 2 . 5² ) : 14 = ( 13 - 8 ) ² - 4²

Answer 1

d , ( x : 7 + 15 ) . 23 + 391 => Đề thiếu

e , ( 19 . x + 2 . 5² ) : 14 = ( 13 - 8 ) ² - 4²

=> ( 19 . x + 2 . 5² ) : 14 = 5² -  16

=> ( 19 . x + 2 . 5² ) : 14 = 25 - 16 = 9

=> 19 . x + 2 . 52 = 9 x 14 = 126

=> 19 . x + 2 . 25 = 126

=> 19 . x + 50 = 126

=> 19 . x = 126 - 50 = 76

=> x = 76 : 19 = 4

Answer 2

a, 230 + [ 2⁴ + ( x - 5 ) ] = 315 . 2020⁰

=> 230 + [16 + ( x - 5 ) ] = 315 . 1

=> 230 + [ ( 16 - 5 ) + x ) = 315

=> 11 + x = 315 - 230 = 85

=> x = 85 - 11 = 74

Answer 3

b, 707 : [ ( 2^x - 5 ) + 74 ] = 4² - 3²

=> 707 : [ ( 2^x - 5 ) + 74 ] = 16 - 9 = 7

=> ( 2^x - 5 ) + 74 = 707 : 7 = 101

=> 2^x - 5 = 101 - 74 = 27

=> 2^x = 27 + 5 = 32

=> 2^x = 2⁵

=> x = 5

Answer 4

c, [ ( 6x - 12 ) : 3 ] . 32 = 64 

=> ( 6x - 12 ) : 3  = 64 : 32 = 2

=> 6x - 12 = 2 x 3 = 6

=> 6x = 6 + 12 = 18

=> x = 3

Answer 5

mình viết lộn phần d 

d, ( x : 7 + 15 ) . 23 = 391

Answer 6

d , ( x : 7 + 15 ) . 23 = 391

=> x : 7 + 15 = 391 : 23 = 17

=> x : 7 = 17 - 15 = 2

=> x = 2 . 7 = 14