You know that the perimeter P is equal to 34 ans that it is the sum of the lengths of the three sides: P = ( 4 x − 1 ) + ( 4 x − 1 ) + x = 34 so: 4 x − 1 + 4 x − 1 + x = 34 isolate x : 9 x = 34 + 2
[tex]4x - 1 + 4x - 1 + x = 34\\\\4x + 4x = 8\\8x + x = 9x\\9x - 1 - 1 = 34\\\\\left \{ {{9x -1+ -1 = 34} \atop {+ 1 = + 1}} \right. \\\\When you have two of the same signs, you add them together.\\so you should end up with -2 so now we have \\9x- 2=34 \\\left \{ {{9x- 2=34 } \atop {+2 + 2}} \right. \\9x = 36\\\left \{ {{{9x= 36} \atop {9\\ \\ \\ \\ \\ \\ \\ 9}\right. \\36 divided by 9 which gives you 4\\so\\ x=4[/tex]