Bài 1 :
a ) 5 + ( x + 27 ) = 64
x + 27 = 64 - 5
x + 27 = 59
x =59 - 27
x=32
b ) 64 - ( x-2 ) =25
x-2 = 64 - 25
x-2 = 39
x = 39 + 2
x = 41
c ) 7 - ( x+ 5 ) + 14 = 343
x + 5 = 343 -14 + 7
x + 5 = 336
x = 336 - 5
x = 331
d ) 5 . x-25 = 10
x - 25 = 10 : 5
x - 25 = 2
x = 2 + 25
x = 27
e) 4 . ( x-5)-8=48
x-5 = (48-8):4
x-5 = 10
x = 10 + 5
x= 15
f) 49 - ( 15 + x ) = 12
15+x=49-12
15+x=37
x=37-15
x=22
g) 49 - 7.(13-x)=14
13-x=(14+49):7
13-x=9
x= 13 - 9
x = 4
h) 155 - 10 . ( x + 1 ) = 55
x +1 = ( 55 + 155 ) : 10
x + 1 = 21
x= 21 - 1
x= 20