РАСКРОЙТЕ СКОБКИ:
(k-y)^2=
(2k-5)^2=
(k^2-5y)^2=

k-y)^2=2k-2y
(k+7)^2=2k+14
(2k-5)^2=4k-25
(4k+3y)^2=16k+9y
(k2-5y)^2=4k-25y
2. 
(*+*)^2=36m^2+*+49n^2
(6m+7n)^2=36m^2+2*6m*7n+49n^2=36m^2+84mn+49n^2