728
a) (2x+3y) ^2 = 4x^2 + 9y^2 + 12 xy
в) (4u - 3t) ^2 = 16u^2 + 9t^2 - 24ut
д) (ab + 2) ^2 = a^2b^2 + 4 + 4ab
ж) (1 - xz) ^2 = 1 + x^2z^2 - 2xz
727
a) 2x^2 + 1 - 4x
б) 25y^2 +1 +10z
в)16z^2 +9 -24 z
г),9a^2 +4 +12a
д)16 + 4b^2 - 16b
е) 9+ 36c^2 + 36c
ж) 1 +4k^2 - 4k
з) 25+ 9r^2 + 30r