The width is x.
The length is 7 meters longer than the width, so it's x+7.
The perimeter is twice the sum of the length and the width. The perimeter is 98 meters.
[tex]2(x+x+7)=98 \\
2(2x+7)=98 \\
4x+14=98 \\
4x=98-14 \\
4x=84 \\
x=\frac{84}{4} \\
x=21 \\ \\
x+7=21+7=28[/tex]
The width is 21 m, the length is 28 m.