(-12)+(x-9)=0
=>x-9=0+12
=>x-9=12
x=12+9
x=21
vậy x=21
\(\left(-12\right)+\left(x-9\right)=0\)
\(-12+x-9=0\)
\(-21+x=0\)
\(x=21\)
Cách 2 : \(\left(-12\right)+\left(x-9\right)=-0\)
\(x-9=12\)
\(x=12+9\)
\(x=21\)
Vậy \(x=21\)
(-12) + (x - 9) = 0
x - 9 = 12
x = 12 + 9
x = 21
(-12) + (x - 9) = 0
=> x - 9 = 0 - (-12)
=> x - 9 = 12
=> x = 12 + 9
=> x = 21
(-12) + (x - 9) = 0
x - 9 = 0 + 12
x - 9 = 12
x = 12 + 9
x = 21
(-12) + (x - 9) = 0
x - 9 = 0 + 12
x - 9 = 12
x = 12 + 9
x = 21
(-12) + (x - 9) = 0
x - 9 = 0 + 12
x - 9 = 12
x = 12 + 9
x = 21
(-12) + (x - 9) = 0
x - 9 = 0 + 12
x - 9 = 12
x = 12 + 9
x = 21
