помогите с алгеброй…

1. (4a+1)²-1=16a²+2×1×4a+1-1=16a²+8a

2. (4a+0,5)²-0,25=16a²+2×0,5×4a+0,25-0,25=16a²+4a

3. (4a+2)²-4=16a²+2×2×4a+4-4=16a²+16a

4. (4a+4)²-16=16a²+2×4×4a+16-16=16a²+32a