Ex1
a) Aire = 6x12² = 6x144 = 864 cm²
Volume = 12³ = 1.728 cm³
b) 20dm=2m, 500cm=5m
Aire=2x(3x2+3x5+2x5)=2x(6+15+10)=62 m²
Volume = 2x3x5 = 30 m³
Ex2
A=(x-1)(x-8)=x²-8x-x+8=x²-9x+8
B=(6a+3)²=36a²+2*3*6a+9=36a²+36a+9
C=(5-3x)²=25-2*5*3x+9x²=25-30x+9x²
D=(2/3x+3)(2/3x-3)=4/9x²-9
Ex3
E=12a-4b+3 : pas de facteur commun
F=x²+10x+25=x²+2*5*x+5²=(x+5)²
G=4t²+36-24t=(2t)²-2*6*2t+6²=(2t-6)²=4(t-3)²
H=121b²-225=(11b)²-15²=(11b+15)(11b-15)