bonjour,
3/5-7/4
3/5=3*4/5*4=12/20
7/4=7*5/4*5=35/20
12/20-35/20=-23/20
(-3/4)*(30/7)=(-3*30)/4*7=-90/28
A=2^5x15^3x21^4/30^4x14^5
15^3=3^3*5^3
21^4=3^4*7^4
30^4=2^4*3^4*5^4
14^5=2^5*7^5
A=2^5*3^3*5^3*2^4*7^4/2^4*3^4*5^4*2^5*7^5
A=2^5*3^3*5^3*2^4*7^4*2^-4*3^-4*5^-4*2^-5*7^-5
A=2^5*2^-9*3^7*3^-4*5^3*5^-4*7^4*7^-5
A=2^-4*3^3*3^-1*7^-1
A=3^3/(2^4*5*7)
A=27/560
B= racine(64*2^5*3^4)
B=racine(2^6x2^5*3^4)
B= racine(2^11*3^4)
B=racine(2^10*2^1*3^4)
B=2^5*3^2(racine(2))
B=32*9*racine(2)
B=288*(racine(2)
