Réponse :
justifier que x ∈[0;8]
x∈[BC]; [BC] = 8cm---> x[0;8]
BM = AB-AM = 10-x
CN = BC-BN = 8-x
A BMN = (MB*BN)/2 = [(10-x)*x]/2= (10x-x²)/2
2) A BMN = (10x-x²)/2
A NPC =[x(8-x)]/2 =(8x-x²)/2
A jaune = (10x-x²+8x-x²)/2 =(18x-2x²)/2 = 9x+x²
a) -(x-4,5)²+20,25=
-(x²-9x+20,25)+20,25=
-x²+9x-20,25+20,25 = -x²+9x
b) -x²-9x=0
x(-x-9)=0
x=9
Explications étape par étape
