Tìm x: (5x + 1)^2 - (5x + 3) (5x - 3) = 302

Tìm x :
1. (5x+1)^2 - (5x+3) (5x-3)=30
2. (x-3)^2 - 4=0
3. 4 (x+1)^2 + (2x -1)^2 - 8 (x+1) (x-1) =11