F.2數學題....因式分解...

左方:
3(Ax +5)(2x +3)
=3(2Ax^2 +3Ax +10x +15)
=6Ax^2 +9Ax +30x +15

右方:
(36x)^2 +Bx +C
=1296x^2 +Bx +C

對照左右兩方的x
6Ax^2 = 1296x^2
6A = 1296
A = 216

9Ax +30x = Bx
9(216)x +30x = Bx
1944x +30x = Bx
1974x = Bx
B = 1974

15 = C
C = 15

so A=216 , B=1974 , C=15

2009-09-12 21:44:22 補充：
修正:
左方:
3(Ax +5)(2x +3)
=3(2Ax^2 +3Ax +10x +15)
=6Ax^2 +9Ax +30x +45

C=45

you can find the value of C first,
put x=0,
3x5x3=C
C=45

put x=-3/2,
then you can find the value of B.

Finally, put x= any value (except 0, -3/2, suggesting put x=1), you can find the value of A.

如果冇計錯同埋後面係成個 36x既2次 ...答案就應該係咁...
A=216,B=1974,C=45