Sagot :
Bonjour,
rappelons que a² = a*a et que ka +kb = k (a+b) et ka-vb = k (a-b)
donc : A = (2x+1) (4x-7) - (2x+1)²
A = (2x+1) (4x-7) - (2x+1) (2x+1)
A = (2x+1) ( 4x-7 - (2x+1) )
A = (2x+1) ( 4x-7 -2x-1)
A = (2x+1) ( 2x-8)
Bonjour
Factoriser :
K=(2x+1)(4x-7)-(2x + 1)²
K = (2x + 1) [(4x - 7) - (2x + 1)]
K = (2x + 1) (4x - 7 - 2x - 1)
K = (2x + 1) (2x - 8)
K = 2 (x - 4) (2x + 1).