Sagot :
A^2=12+10V3+25=37+10V3 ; B^2=12-10V3+25=37-10V3 et A*B=12-25=-13
A²=(2V3+5)x(2V3+5)=2V3x2V3 +2V3x5+5x2V3+5x5=12+10V3+10V3+25=37+20V3
B²=(2V3-5) x(2V3-5)=2V3x2V3-2V3x5-5x2V3+5x5=12-10V3-10V3+25=37-20V3