a, 11-(15+11)=x-(25-9)
\(\Leftrightarrow11-26=x-16\)
\(\Leftrightarrow x=-16-11+26\)
\(\Leftrightarrow x=-1\)
b, 2-x=17-(-5)
\(\Leftrightarrow2-x=22\)
\(\Leftrightarrow-x=22-2\)
\(\Leftrightarrow x=-20\)
c, x-(17-x)=x-7
\(\Leftrightarrow x-17+x=x-7\)
\(\Leftrightarrow x+x-x=-7+17\)
\(\Leftrightarrow x=10\)
Bài 1 :
a, Ta có : \(11-\left(15+11\right)=x-\left(25-9\right)\)
=> \(11-15-11-x+25-9=0\)
=> \(x=1\)
b, Ta có : \(2-x=17-\left(-5\right)\)
=> \(2-x=22\)
=> \(x=-20\)
c, Ta có : \(x-\left(17-x\right)=x-7\)
=> \(x-17+x-x+7=0\)
=> \(x=10\)