1. (х-1)^2 = x^2-2*1*x+1^2 = x^2 - 2x + 1
2. (3a-b)^2 = (3a)^2 - 2*3a*b + b^2 = 9a^2 - 6ab + b^2
3. (5z+t)^2 = 25z^2 +10zt + t^2
4. (6m-4n)^2 = 36m^2 - 48mn + 16n^2
5. (x+c)^2 = x^2 +2xc + c^2
6. (a-4)^2 = a^2 - 8a + 16
7. (0.2a+b)^2 = 0.04a^2 + 0.4ab + b^2
как я поняла