Bài 2:
a,$\sqrt[]{(-3)^{6} }$ =$\sqrt[]{3^{6}}$=$\sqrt[]{3^{4}.3^{2}}$=$3^{2}$.3=9.3=27
b,$\sqrt[]{(3-√3)^{2}}$=|3-√3|=3-√3 (vì 3-√3>0)
c,$\sqrt[]{(4-√17)^{2}}$=|4-√17|=√17-4 (vì 4-√17 <0)
d,$\sqrt[]{15^{2}-12^{2}}$
=$\sqrt[]{(15-12)(15+12)}$
= $\sqrt[]{3.27}$
=$\sqrt[]{81}$=9
e,$\sqrt[]{(4-√17)^{2}}$=|4-√17|=√17-4 (vì 4-√17 <0)
f,$\sqrt[]{15^{2}-12^{2}}$
=$\sqrt[]{(15-12)(15+12)}$
= $\sqrt[]{3.27}$
=$\sqrt[]{81}$=9
g,$\sqrt[]{12-6√3}$
=$\sqrt[]{(3-√3)²}$
=|3-√3|=3-√3 (vì 3-√3>0)
h,$\sqrt[]{23+8√7}$-√7
=$\sqrt[]{(4+√7)^{2}}$-√7
=|4+√7|-√7=4+√7-√7=4
i,2√3+$\sqrt[]{7-4√3}$
=2√3+$\sqrt[]{(2-√3)^{2}}$
=2√3+|2-√3|=2√3+2-√3=2+√3
