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halosh92:
ive got a college exam coming up in 2 days for maths
c1, c2 and probably c3 and c4...
could someone help me out with these questions plz
thxxxx


x^4 - 625

which are the following are its factors ???
a) x - 5
b) x + 5
c) x^2 + 25

is it a)
 or b)
or c)
 or (a) and (b)  
or all of them ?

cooldude:

--- Quote from: halosh92 on August 06, 2010, 05:36:22 pm ---ive got a college exam coming up in 2 days for maths
c1, c2 and probably c3 and c4...
could someone help me out with these questions plz
thxxxx


x^4 - 625

which are the following are its factors ???
a) x - 5
b) x + 5
c) x^2 + 25

is it a)
 or b)
or c)
 or (a) and (b)  
or all of them ?
 


















--- End quote ---

this is of the form a^2-b^2=(a+b)(a-b)
root x^4=x^2 and root 625=25
therefore (x^2+25)(x^2-25), now we again use the identity
(x^2+25)(x+5)(x-5)
therefore a,b and c are correct

Alpha:
ALL 3 are correct.

You know the concept: difference of perfect squares?

x^4 - 625 = (x^2)^2 - 5^4
         
                = (x^2)^2 - (5^2)^2

                = (x^2 - 5^2)(x^2 + 5^2)

                = (x - 5)(x + 5)(x^2 + 25)

halosh92:
thx to both of you <3

halosh92:
am sorry the questions are basic
but could u gimmi the answer for this

2^40 + 2^40+ 2^40 + 2^40
???

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