Répondre :
1) f=(5x+4)^2-49=25x^2+40x+16-49=25x^2+40x-33
2) f=(5x+4)^2-7^2=(5x+4-7)(5x+4+7)=(5x-3)(5x+11)
2) f=(5x+4)^2-7^2=(5x+4-7)(5x+4+7)=(5x-3)(5x+11)
2
on considere l expression f=(5x+4)-49 1) developper puis reduire F 2)factoriser F 3) resoudre l equation (5x-3)(5x+ 11)=0 4)calculer F pour x=-2