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If-x-2-3x-1-0-then-find-the-value-of-x-2-x-1-x-1-x-2-2-




Question Number 191552 by MATHEMATICSAM last updated on 25/Apr/23
If x^2  − 3x + 1 = 0 then find the value of  (x^2  + x + (1/x) + (1/x^2 ))^2
Ifx23x+1=0thenfindthevalueof(x2+x+1x+1x2)2
Answered by mr W last updated on 25/Apr/23
x^2 −3x+1=0  ⇒x+(1/x)=3  (x^2 +x+(1/x)+(1/x^2 ))^2   =(x+(1/x)+x^2 +(1/x^2 ))^2   =[(x+(1/x))+(x+(1/x))^2 −2]^2   =(3+3^2 −2)^2   =100 ✓
x23x+1=0x+1x=3(x2+x+1x+1x2)2=(x+1x+x2+1x2)2=[(x+1x)+(x+1x)22]2=(3+322)2=100
Answered by Rasheed.Sindhi last updated on 26/Apr/23
AnOther Way...  x^2  − 3x + 1 = 0⇒1=3x−x^2 =x(3−x)  (x^2  + x + (1/x) + (1/x^2 ))^2   =(x^2  + x + ((x(3−x))/x) + ((x(3−x))/x^2 ))^2   =(x^2  + x + 3−x + ((3−x)/x))^2   =(x^2   + 3 + ((3−x)/x))^2   =(((x^3 +3x+3−x)/x))^2   =(((x^3 +2x+3×1)/x))^2   =(((x^3 +2x+3x(3−x))/x))^2   =(((x^3 +2x+9x−3x^2 )/x))^2   =(x^2 −3x+1+10)^2   =(0+10)^2 =100 ✓
AnOtherWayx23x+1=01=3xx2=x(3x)(x2+x+1x+1x2)2=(x2+x+x(3x)x+x(3x)x2)2=(x2+x+3x+3xx)2=(x2+3+3xx)2=(x3+3x+3xx)2=(x3+2x+3×1x)2=(x3+2x+3x(3x)x)2=(x3+2x+9x3x2x)2=(x23x+1+10)2=(0+10)2=100

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