Tìm x , biết a) [( 10 – x ) . 2 + 51 ] : 3 – 2 = 3 b) ( 12x – 43 ) . 8^3 = 4 . 8^4 c) 720 – [ 41 – ( 2x – 5 ) ] = 2^x . 5

0 bình luận về “Tìm x , biết a) [( 10 – x ) . 2 + 51 ] : 3 – 2 = 3 b) ( 12x – 43 ) . 8^3 = 4 . 8^4 c) 720 – [ 41 – ( 2x – 5 ) ] = 2^x . 5”

1. Đáp án:

    

   Giải thích các bước giải:

    a)[(10-x).2+51]:3=3+2

   [(10-x).2+51]:3=5

   (10-x).2+51=5.3

   (10-x).2+51=15

   (10-x).2=15-51

   (10-x).2=-36

   10-x=-36:2

   10-x=-18

   x=10-(-18)

   x=28

   Bình luận

2. )[(10-x).2+51]:3=3+2

   [(10-x).2+51]:3=5

   (10-x).2+51=5.3

   (10-x).2+51=15

   (10-x).2=15-51

   (10-x).2=-36

   10-x=-36:2

   10-x=-18

   x=10-(-18)

   x=28

   b)( 12x – 43 ) . 8^3 = 4 . 8^4

   (12x-43).8³=4.4096

   (12x-43).8³=16384

   12x-43=16384:512

   12x-43=32

   12x=32+43

   12x=75

   x=75:12

   x=6.25

   c) 720 – [ 41 – ( 2x – 5 ) ] = 2^x . 5

   720-[41-(2x-5)]=

   720-[41-(2x-5)]=

   720-[41-

   Bình luận