Answer: Length=10.5
Step-by-step explanation: P=34 and W=6.5. This can also be known as Perimeter=W+L+W+L=2(W+L). In this case, it would be 34= 2(6.5 +L). 34=13+2L.(The 2L's are crossed out now because they cancel both out)
-2L -2L (There is a line going down at the equal sign.
34+-2L=13 Subtract 34 from both sides and cancel the two 34's out)
-34 -34
-2L=-21 (Divide both sides by -2) (Cancel out the -2's)
/-2 /-2
L = 10.5