Question

问几个数学问题。。 1）（7+3√5）开根号+（7-3√5）开根号 2）(√6+4√3+3√2)÷【(√6+√3)(√3+√2)】

Answer 1

(1) 7+3√5=(14+6√5)/2=(3+√5)^2/2 7-3√5=(3-√5)^2/2 所以你要求的为3√2
(2) (√6+4√3+3√2)/[(√6+√3)(√3+√2)]=[(√6+√3)+3(√3+√2)]/[(√6+√3)(√3+√2)]=1/(√3+√2)+3/(√6+√3)
=√3-√2+√6-√3=√6-√2

Answer 2

(1)将原式平方:[√(7+3√5)+√(7-3√5)]^2=14+2√(7+3√5)(7-3√5)=14+2*2=18
所以原式=3√2
(2)分子分母同乘以(√6-√3)(√3-√2),得:
[(√6+4√3+3√2)(√6-√3)(√3-√2)]/(6-3)=[(√6+4√3+3√2)(3√2-2√3-3+√6)]/3
=(6√3-6√2-3√6+6+12√6-24-12√3+12√2+18-6√6-9√2+6√3)/3
=√6-√2
没拿笔算，答案不一定对，思路不会错，你验证一遍

Answer 3

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