複合根式的化簡

(a+b+c)²=a²+b²+c²+2ab+2ac+2bc(a+b√3+c√7)²=a²+2ab√3+2ac√7+3b²+2bc√21+7c²ab=8,ac=6,bc=4,abc=8√3c=√3,a=2√3,b=4/√3Ans:4+2√3+√21 x=³√(110√7+279)+³√(110√7-279)x³-57x-220√7=0x=k√77k³-57k-220=0k=4,x=4√7[4√7+√(112-76)]/2=3+2√7Ans:3+2√7 (a+b+c)³=a³+b³+c³+3a²b+3a²c+3ac²+3b²c+3bc²+3ab²+6abc(a+b√5+c√7)³=a³+5b³√5+7c³√7+3a²b√5+3a²c√7+21ac²+15b²c√7+21bc²√5+15ab²+6abc√35abc=24=2x2x2x3a(a²+15b²+21c²)=940=2x2x5x47b(3a²+5b²+21c²)=531=3x177c(3a²+15b²+7c²)=422=2x211a=4,b=3,c=2Ans:4+3√5+2√7