（1）（3x-2y)^2=9x^2+(?)-(?)(2)(-3a^2-b)^2=(?)+b^2+(?)(3)(?+2c)^2=25t^2+4c^2+(?)(4)(?+1/2a)^2(4)(?+1/2a)^2=?+1/4a^2-ab

（1）（3x-2y)^2=9x^2+(?)-(?)(2)(-3a^2-b)^2=(?)+b^2+(?)(3)(?+2c)^2=25t^2+4c^2+(?)(4)(?+1/2a)^2(4)(?+1/2a)^2=?+1/4a^2-ab
（1）（3x-2y)^2=9x^2+(?)-(?)(2)(-3a^2-b)^2=(?)+b^2+(?)(3)(?+2c)^2=25t^2+4c^2+(?)(4)(?+1/2a)^2
(4)(?+1/2a)^2=?+1/4a^2-ab

（1）（3x-2y)^2=9x^2+(?)-(?)(2)(-3a^2-b)^2=(?)+b^2+(?)(3)(?+2c)^2=25t^2+4c^2+(?)(4)(?+1/2a)^2(4)(?+1/2a)^2=?+1/4a^2-ab
（1）（3x-2y)^2=9x^2+(?)-(?)
（3x-2y）^2=9x^2+4y^2-12xy
(2)(-3a^2-b)^2=(?)+b^2+(?)
(-3a^2-b)^2=9a^4+b^2+6a^2b
(3)(?+2c)^2=25t^2+4c^2+(?)
(5t+2c)^2=25t^2+4c^2+20tc
(4)(?+1/2a)^2=?+1/4a^2-ab
(-b+1/2a)^2=b^2+1/4a^2-ab