Question

Bài 1:Tìm x , biết :

a,    (x-12) -15 = (20-7) - (18+x)

b,     x- 96  = ( 443 - x) - 15

c,     311 - x + 82 = 46 + ( x- 21)

d,     - ( x - 3 + 85) = ( x + 70 - 71) -5

e,     ( - x + 821 + 534 ) = 499 + ( x-84)

f,      x + 96 = ( 443 - x) - 447

Answer 1

a,    (x-12) -15 = (20-7) - (18+x)

<=> x - 12 - 15 = 13 - 18 - x 

<=> 2x = 22

<=> x = 11

b,     x- 96  = ( 443 - x) - 15

<=> x - 96 = 443 - x - 15

<=> 2x = 524

<=> x = 262

c,     311 - x + 82 = 46 + ( x- 21)

<=> 311 - x + 82 = 46 + x - 21

<=> 2x = 368

<=> x = 184

Answer 2

e,     ( - x + 821 + 534 ) = 499 + ( x-84)

<=> - x + 821 + 534 = 499 + x - 84

<=> 2x = 940

<=> x = 470

f,      x + 96 = ( 443 - x) - 447 

<=> x + 96 = 443 - x - 447

<=> 2x = - 100

<=> x = - 50

Answer 3

d,     - ( x - 3 + 85) = ( x + 70 - 71) -5

<=> - x + 3 - 85 = x + 70 - 71 - 5

<=> 2x = - 76

<=> x = - 38