How do I find the weight in pounds of and bald eagle who's wing span is 7 feet. and my equation is L = 2.43 * W ^ 0.3326 to estimate the bird weight W in pounds, so how can I find out how much the 7 feet wing weigh in pound.

Substitute L=7 to get

7=2.43*W^0.3326
W^0.3326=7/2.43=2.88
log(W^0.3326)=log(2.88)
0.3326log(W)=log(2.88)
log(W)=log(2.88)/0.3326
W=10^(log(2.88)/0.3326)
=24 lbs