(x-12)-15 = (20-7)-(18+x)
x-12-15 = 20-7-18-x
x-27 = -5-x
=> x-27+5+x = 0
2x-25 =0
2x = 0+25 = 25
Chúc bạn học tốt !
(x - 12) -15 = (20 - 7) - (18 + x)
x - 12 -15 = 20 - 7 - 18 - x
x - 27 = -5 - x
x - 27 + 5 + x = 0
2x - 22 = 0
2x = 0 + 22
2x = 22
x = 22 : 2 = 11
( x - 12 ) - 15 = ( 20 - 7 ) - ( 18 + x )
=> x - 12 - 15 = 20 - 7 - 18 - x
=> x - 12 + x = 20 - 7 - 18 + 15
=> x + x - 12 = 10
=> 2x = 10 + 12
=> 2x = 22
=> x = 22 : 2
=> x = 11
Vậy x = 11