Question

If x square - x-1=0,find the value of x cube-2x+1 is​

Answer 1

Answer:

(1±i√3)/2

Step-by-step explanation:

x²-x-1=0 -----@

x²=x+1

x³-2x+1= x².x-2x+1

= (x+1)x -2x +1

= x²+x-2x+1

= x²-x+1

apply quadratic equation

x =(1±√-3)/2

x= (1±i√3)/2

Answer 2

Answer:

${x}^{2 } - x - 1 = 0$

${x }^{2} = 1 + x$

To find : value of x^3-2x+1

${x}^{3 } - 2x + 1 = x(x + 1) - 2x + 1 \\ = {x}^{2} + x - 2x + 1 \\ = (x + 1) - x + 1 \\ = 2$

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