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Mathematics 8 Online
OpenStudy (anonymous):

Show that x-m is a factor of x^a-m^a for any positive integer a.

OpenStudy (dumbcow):

(x-m) is only a factor if m is a zero let x=m m^a - m^a = 0

OpenStudy (anonymous):

thanks :)

hartnn (hartnn):

that true for any value of a, not just positive integer, right ?

OpenStudy (anonymous):

what is the answer? zero only?

hartnn (hartnn):

yeah, for x-m to be the root, x^m-a^m must be = 0 for x=m

OpenStudy (anonymous):

thanks :)

OpenStudy (dumbcow):

they want answer in form of a proof

OpenStudy (dumbcow):

uh oh what did i do :) @CarlosGP

hartnn (hartnn):

carlos, please elaborate

OpenStudy (anonymous):

Last 1 Pls help. The Polynomial 3X^2+bx-4 has x-a as a factor where a is not equal to zero. express b in terms of a. @hartnn pls help

hartnn (hartnn):

since x-a is factor, x=a will satisfy 3X^2+bx-4 =0 so, just plug in x=a in that and solve a quadratic equation

hartnn (hartnn):

3a^2+ab-4=0 can u solve this ?

OpenStudy (anonymous):

not really.

hartnn (hartnn):

you know quadratic formula ?

OpenStudy (anonymous):

no.

hartnn (hartnn):

compare the equation 3a^2+ab-4 = 0 to Aa^2+Bb+C = 0 what are A,B, C =... ?

hartnn (hartnn):

is that confusing to you ?

hartnn (hartnn):

***Aa^2+Ba+C = 0

OpenStudy (anonymous):

I'm really confused. pls show show the steps on how to answer it

hartnn (hartnn):

comparing 3a^2+ab-4 = 0 with Aa^2+Ba+C = 0 we get A=3, B=b and C= -4 now just use the formula \(\large a= \dfrac{-B \pm \sqrt{B^2-4AC}}{2A}\)

OpenStudy (anonymous):

@hartnn i dont know how to use that formula \(\large a= \dfrac{-B \pm \sqrt{B^2-4AC}}{2A}\)

OpenStudy (anonymous):

@hartnn pls help

hartnn (hartnn):

just plug in A=3, B=b and C= -4 in that expression!

OpenStudy (anonymous):

we should divide x^a-m^a by x-m

OpenStudy (anonymous):

i think like this: (x-m)(x^(a-1)+mx^(a-2)+m^2 x^a-3+...

OpenStudy (anonymous):

same problem here! The Polynomial 3X^2+bx-4 has x-a as a factor where a is not equal to zero. express b in terms of a.

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