Question

3. If x2 + 1/x2 = 34 find x3 +1/x3
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Answer 1

using first square formula and then cubic formula

Step-by-step explanation:

using square formula for this equation

$(x+1/x)^{2}= (x^{2}+1/x^{2}+2)$

$(x+1/x)^{2}= 34+2$

$(x+1/x)^{2}= 36$

$(x+1/x)= 6$

now using the cubic formula

$(x+1/x)^{3} = (x^{3}+(1/x)^{3}+3\times (x+1/x)$

$(6)^{3}-3(6)= (x^{3}+(1/x)^{3}$

$216-18= (x^{3}+(1/x)^{3}$

$198= (x^{3}+(1/x)^{3}$