A = (x+1)² = a²+2×a×b+b² = x²+2×x×1+1²
= x²+2x+1
B = (x+5) (x-5) = a²- b² = x²- 5² = x²- 25
C = (4-x)² = a²-2×a×b+b² = 4²-2×4×x+x² = 16-8x+x²
D = (x-2,5)² = a²-2×a×b+b²= x²-2×x×2,5+2,5² = x²-5x+ 6,25
E = (1-x) (1+x) = a²-b²= 1²-x² = 1-x²
F = (6+x)² = a²+2×a×b+b² = 6²+2×6×x+x² = 36+12x+x²
G= (x-3) (x+3) = a²-b² = x²-3² = x²-9
