Answer :
1. (t-5)^2+3=t^2-10t+12+3=t^2-10t+15.
2. (a+h)^2+3=a^2+2ah+h^2+3
(a^2)+3=a^2+3. Subtracting, we get h^2+2ah.
3. (a^2)+3=a^2+3
(a-h)^2+3=a^2-2ah+h^2+3. Subtracting, we get 2ah-h^2.
2. (a+h)^2+3=a^2+2ah+h^2+3
(a^2)+3=a^2+3. Subtracting, we get h^2+2ah.
3. (a^2)+3=a^2+3
(a-h)^2+3=a^2-2ah+h^2+3. Subtracting, we get 2ah-h^2.