Sagot :
Bsr
D = 5r-25c
D = 5(r-5x)
E = 48xy-6x+18x
E = 48xy+12x
E = 12x(4y+1)
F = (x-1)(4-3x)-(x-1)(8+6x)
F = (x-1)(4-3x-(8+6x))
F = (x-1)(4-3x-8-6x)
F = (x-1)(-4-3x-6x)
F = (x-1)(-4-9x)
Voilà !
Bsr
D = 5r-25c
D = 5(r-5x)
E = 48xy-6x+18x
E = 48xy+12x
E = 12x(4y+1)
F = (x-1)(4-3x)-(x-1)(8+6x)
F = (x-1)(4-3x-(8+6x))
F = (x-1)(4-3x-8-6x)
F = (x-1)(-4-3x-6x)
F = (x-1)(-4-9x)
Voilà !