bonjour

1/ developper

b = 4x(5x-2) +25x²-4

b = 20x²-8x+25x²-4

b = 45x²-8x-4

2/ factoriser  25x²-4 = (5x-2)(5x+2)

en deduire une .......

b = 4x(5x-2) +25x²-4

b = 4x(5x-2) +(5x-2)(5x+22)

b =(5x-2)(4x+5x+2)

b =(5x-2)(9x+2)