5 - ( 2x - 7 ) = 3 . ( -4) + 20
5 - ( 2x - 7 ) = ( -12 ) + 20
5- ( 2x - 7 ) = 8
2x - 7 = 5 - 8
2x - 7 = -3
2x = -3 + 7
2x = 4
x = 4 : 2
x = 2
chúc bn hok tốt
5 - ( 2x - 7 ) = 3 . ( -4) + 20
5 - ( 2x - 7 ) = ( -12 ) + 20
5- ( 2x - 7 ) = 8
2x - 7 = 5 - 8
2x - 7 = -3
2x = -3 + 7
2x = 4
x = 4 : 2
x = 2
Tìm x :
5 - ( 2x + 7 ) = 3 . ( -4 ) + 20
<=> 5 - ( 2x + 7 ) = ( -12 ) + 20
<=> 5 - ( 2x + 7 ) = 8
<=> 2x + 7 = 5 - 8
<=> 2x + 7 = -3
<=> 2x = (-3) - 7
<=> 2x = -10
<=>x = ( -10 ) : 2
<=>x = -5
Vậy x = -5