a) x - 7 = -5
=> x = -5 + 7
=> x = 2
b) 128 - 3 . (x + 4) = 23
=> 3.( x + 4) = 128 - 23
=> 3.( x + 4) = 105
=> x + 4 = 105 : 3
=> x + 4 = 35
=> x = 35 - 4
=> x = 31
c) [ ( 6x - 39 ) : 7 ].4 = 12
( 6x -39) : 7 = 12 :4
=> ( 6x - 39 ): 7 = 3
=> 6x - 39 = 3 x 7
=> 6x - 39 = 21
=> 6x = 21 + 39
=> 6x = 60
=> x = 60: 6
=> x = 10
d) ( x: 3 - 4) , 5 = 15
=> x: 3 - 4 = 15 : 5
=> x : 3 - 4 = 3
=> x: 3 = 3+4
=> x: 3 = 7
=> x = 7x 3
=> x =21
a) x -7=-5
x=-5 +7
x=2
b)128-3.(x+4)=23
3.(x+4)=128-23
3.(x+4)=105
x+4=105:3
x+4=35
x=35-4
x=31
c)[(6x-39):7].4=12
(6x-39):7=12:4
(6x-39):7=3
6x-39 =3.7
6x-39 =21
6x =21+39
6x =60
x =60:6
x =10
d)(x:3-4).5=15
x:3-4. =15:5
x:3-4 =3
x:3 =3+4
x:3 =7
x =7.3
x =21
Ai thấy đúng k mk nha
Để mk giúp bn nhé:
a,x-7=-5
x=-5+(-7)
x=-12
b,128-3.(x+4)=23
3.(x+4)=128-23
3.(x+4)=105
x+4=105 :3
x+4=35
x=35-4
x=31
c,[(6x-39):7].4=12
(6x-39):7=12:4=3
6x-39=3x7
6x-39=21
6x=21+39
6x=60
x=60:6
x=10
d,(x:3-4).5=15
(x:3-4)=15:5
x:3-4=3
x:3=3+4
x:3=7
x=7.3
x=21
a)x - 7 = -5 b)128 - 3 . (x+4)= 23 c) [ (6x - 39) : 7] . 4=12 d)(x : 3 - 4) . 5=15
x=-5 +7 3 . (x+4)= 128 - 23 [(6x - 39) : 7]=12:4 x : 3 - 4 = 15 :5
x=2 3 . (x+4)=105 (6x - 39) : 7=3 x:3 - 4 = 3
x+4=105 : 3 6x - 39=3 . 7 x : 3 = 3+4
x+4=35 6x - 39=21 x :3 = 7
x=35 - 4 6x=21 + 39 x=7 . 3
x=31 6x=60 x = 21
x=60 : 6
x=10
a, x - 7 = -5
x = -5 + 7
x = 2
b, 128 -3.(x + 4 ) = 23
3.(x+4 ) = 128 - 23
3.(x + 4 ) = 105
x + 4 = 105 : 3
x + 4 = 35
x = 35 - 4
x = 31
c, [ ( 6x - 39 ) : 7 ] .4 = 12
[ ( 6x - 39 ) : 7 ] =12 : 4
[ ( 6x - 39 ) : 7 ] = 3
6x - 39 = 3.7
6x - 39 = 21
6x = 21 + 39
6x = 60
x = 60 : 6
x = 10
d, ( x : 3 - 4 ) . 5 = 15
x : 3 - 4 = 15 : 5
x : 3 - 4 = 3
x : 3 = 3 + 4
x : 3 = 7
x = 7.3
x = 21