2a=3b2a=3b求4a²+12ab+9a²/2a²+5ab+3b²

2a=3b2a=3b求4a²+12ab+9a²/2a²+5ab+3b²
2a=3b2a=3b求4a²+12ab+9a²/2a²+5ab+3b²

2a=3b2a=3b求4a²+12ab+9a²/2a²+5ab+3b²
应该是：（4a²+12ab+9b²）/（2a²+5ab+3b²）
=(2a+3b)^2/(2a+3b)(a+b)
=(2a+3b)/(a+b)
代入：2a=3b
=(3b+3b)/(b+3b/2)
=6b/(5b/2)
=6/(5/2)
=6*2/5
=12/5

∵2a=3b，
∴a=3b/2
(4a²+12ab+9b²)/(2a²+5ab+3b²)
=(2a+3b)²/(2a+3b)(a+b)
=(2a+3b)/(a+b)
=(3b+3b)/(3b/2+b)
=6b/(5b/2)
=12/5