Réponse :
Bonjour ;
Explications étape par étape
1) (-2)² = -4
-(-5)² = +25
-7² = -49
1/2 x 3^4/(3²)² = 1/2x3^4/3^4 =1/2
2)
7^4 x(7^3)²= 7^4 x 7^6 = 7^10
-5^3 x 5^7/5^5 = -5^10/5^5 = -5^5
1000x (10²)^9 / 10^3 x 10^3 = 10^3x10 ^18 /10^6 =10^21 /10^6 = 10^15
3) E11 = a^3xa/(a²)² = a^4/a^4 = 1
E12 = a^5 x( a x a²)^3 /(b²)7 = a^5xa^9/b^14 =a^14/b^14
