help with factoring by grouping

lsosa02

New member
Joined
Apr 5, 2006
Messages
17
i would appreciate anyones help with this problem . Thank you.

the problem is: acx^m+n+adx^n+bcx^m+bd

the directions say to factor this into two groups . To assume that a,b,c and dare constants . Then it says to varify the factorization by multipliying .

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acx^(m+n)+adx^n+bcx^m+bd
Grouping as
ax^n*(cx^m+d)+b(cx^m+d)
It factors into
(ax^n+b)(cx^m+d)
 
Hello, lsosa02!

How about using parentheses and spaces?
It's really difficult to guess what you meant . . .

Factor: \(\displaystyle acx^{m+n}\,+\,adx^n\,+\,bcx^m\,+\,bd\)

The directions say to factor this into two groups and assume that a,b,c and dare constants.
Then it says to varify the factorization by multipliying.
Factor the first two terms: \(\displaystyle \,acx^{m+n}\,+\,adx^n\)
They have a common factor: \(\displaystyle \,ax^n\)
Factor it out: \(\displaystyle \,ax^n(cx^m\,+\,d)\)

Factor the last two terms: \(\displaystyle \,bcx^m\,+\,bd\)
They have a common factor: \(\displaystyle \,b\)
Factor it out: \(\displaystyle \,b(cx^m\,+\,d)\)

We have: \(\displaystyle \,ax^n(\underbrace{cx^m\,+\,d})\,+\,b(\underbrace{cx^m\,+\,d})\)
. . . . . . . . Do you see the common factor?

Factor it out: \(\displaystyle \:(cx^m\,+\,d)\,(ax^n\,+\,b)\;\;\) . . . There!

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Check

Multiply it out ("FOIL") . . .

We have: \(\displaystyle \,(cx^m\,+\,d)(ax^n\,+\,b)\)

\(\displaystyle \;\;\;=\;(cx^m)(ax^n)\,+\,(cx^m)(b)\,+\,(d)(ax^n)\,+\,(d)(b)\)

\(\displaystyle \;\;\;=\;acx^{m+n}\,+\,bcx^m\,+\,adx^n\,+\,bd\;\;\) . . . check!
 
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