<=> 11 - 15 - x = x - 25 + 9
<=> -x - x = - 25 + 9 - 11 + 15
<=> - 2x = -12
<=> x = -12 : (- 2)
<=> x = 6
Tìm số nguyên x biết:
\(11-\left(15+x\right)=x-\left(25-9\right)\)
\(11-\left(15+x\right)=x-16\)
\(11-15-x=x-16\)
\(-x-x=-16-11+15\)
\(-2x=-16-11+15\)
\(-2x=-27+15\)
\(-2x=-12\)
\(-x=-12:2\)
\(-x=-6\)
\(=>x=6\)
Vậy \(x=6\)