Perimeter = length of all sides added together
[tex]102=(3x+5)+(3x+5)+(7x-4)+(7x-4)[/tex]
[tex]102=2(3x+5)+2(7x-4)[/tex]
[tex]102=6x+10+14x-8[/tex]
[tex]102=20x+2[/tex]
[tex]102-2=20x[/tex]
[tex]100=20x[/tex]
[tex]x= \frac{100}{20} [/tex]
[tex] \left[\begin{array}{ccc}x=5\end{array}\right] [/tex]
Hope this helped
