If a and b are the roots of the equation x2-2x-7=0, then a-b is

If a and b are the roots of the equation x2-2x-7=0, then a-b is

About the author
Alice

2 thoughts on “If a and b are the roots of the equation x2-2x-7=0, then a-b is”

  1. Answer:

    x2+2x+2=0

    Here, a=1,b=2,,c=2

    From quadratic formula,

    x=2×1−2±22−4×2×1

    ⇒x=2−2±2i=−1±i

    Therefore,

    α=−1+i⇒α2=(−1+i)2=−2i

    β=−1−i⇒β2=(−1−i)2=2i

    Now,

    α15+β15

    =(α2)7⋅α+(β2)7⋅β

    =(−2i)7(−1+i)+(2i)7(−1−i)

    =(−2)7(−i)(−1+i)+27(−i)(−1−i)

    Reply

Leave a Reply to Caroline Cancel reply