\(7^2-7\left(13-x\right)=14\)
\(7\left(13-x\right)=49-14=35\)
\(13-x=35:7=5\)
=> \(x=13-5=8\)
\(7^2-7\left(13-x\right)=14\)
\(49-7\left(13-x\right)=14\)
\(7\left(13-x\right)=49-14\)
\(7\left(13-x\right)=35\)
\(13-x=\frac{35}{7}\)
\(13-x=5\)
\(x=13-5\)
\(x=8\)
49-91+x=14
-42+x=14
x=14+42=56
k cho mk nhé Nguyễn Trần Hồng Ngọc