Répondre :
A=2(√11-3)/(√11+3)
=2(√11-3)²/((√11+3)(√11-3))
=(2(11+9-6√11))/(11-9)
=20-6√11
B=5/(√3-2)-2/(√3+2)
=5(√3+2)/((√3-2)(√3+2))-2(√3-2)/((√3+2)(√3-2))
=(5√3+10)/(3-4)-(2√3-4)/(3-4)
=-5√3-10+2√3-4
=-3√3-14
=2(√11-3)²/((√11+3)(√11-3))
=(2(11+9-6√11))/(11-9)
=20-6√11
B=5/(√3-2)-2/(√3+2)
=5(√3+2)/((√3-2)(√3+2))-2(√3-2)/((√3+2)(√3-2))
=(5√3+10)/(3-4)-(2√3-4)/(3-4)
=-5√3-10+2√3-4
=-3√3-14