How do you use the factor theorem to determine whether x=5 is a root of $x^4-3x^3-9x^2-5x=0$ ?

Question

1537 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-03-28T13:19:00

$x=5" is a root"$

$"if x = 5 is a root then if "f(5)=0" x = 5 is a root"$

$rArr(5)^4-3(5)^3-9(5)^2-5(5)$

$=625-375-225-25=0$

$rArrx=5" is a root"$

How do you use the factor theorem to determine whether x=5 is a root of x^4-3x^3-9x^2-5x=0x^4-3x^3-9x^2-5x=0?