Posted by jesus on Wednesday, May 7, 2008 at 11:46pm.
(4b+5c)(4c+3b)=

algebra  Ryan, Thursday, May 8, 2008 at 12:46am
16bc+12b(squared)+20c(squared)+15bc
12b(squared)+ 20c (squared)+ 31bc 
algebra  PsyDAG, Thursday, May 8, 2008 at 12:26pm
(4b+5c)(4c+3b) = (4b+5c)(3b+4c)
4b + 5c
3b + 4c
Multiplying
16bc+20C^2
12b^2+15bc
= 12b^2+31bc+20c^2
I hope this makes the process clearer. Thanks for asking.