2130-(x+130)+72=-64
2130-(x+130)=-64-72
2130-(x+130)=-136
x+130=2130-(-136)
x+130=2130+136=2266
x=2266-130
x=2136
b)x-(-x+15)=17
=>x+x-15=17
=>2x-15=17
=>2x=17+15=32
x=16
đúng thì ****
a) 2130 - ( x + 130 ) + 72 = -64
( x + 130 ) + 72 = 2130 - -64
( x + 130 ) + 72 = 2194
( x + 130 ) = 2194 - 72
x + 130 = 2122
x = 2122 - 130
x = 1992