Sagot :
Bonjour,
Ex. 1 :
figure 1 : aire du carré = a² + ba + ab + b²
figure 2 : aire du carré = (a+b)²
(a+b)² = (a+b)(a+b) = a²+ab+ba+b² = a²+2ab+b²
(a+b)² = a²+2ab+b²
donc : (8+a)² = 8²+2(8)(a)+a² = 64+16a+a²
(x+y)² = x²+2xy+y²
(a+3)² = a²+2(a)(3)+3² = a²+6a+9
....etc.....etc.....
102² = (100+2)² = 100²+2(100)(2)+2² = 10 000 + 400 + 4 = 10 404
45² = (40+5)² = 40²+2(40)(5)+5² = 1 600 + 400 + 25 = 2 025
....etc.....etc....
