
Amy M. answered 03/07/15
Tutor
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CalTech Grad, Software engineer with 30+ years experience.
It took me awhile to understand the question. The polynomial
9x^2+5x+2
is being divided by 4x+1
4x+1| 9x^2+5x+2
If you multiply the 4x polynomial by 9x/4 the product will yield the term 9x^2 The first term of the second order polynomial so let's try that
9x/4
4x+1| 9x^2+5x+2
9x^2+9x/4
The bottom line is the product of (4x+1) and 9x/4
as in long division subtract
9x/4
4x+1| 9x^2+5x. +2
9x^2+9x/4
4x+1| 9x^2+5x. +2
9x^2+9x/4
11x/4 +2
this last line is the difference of the second order polynomial and the polynomial resulting from the product of 9x/2 and 4x+1
this last line is the difference of the second order polynomial and the polynomial resulting from the product of 9x/2 and 4x+1
now if we multiply by 11/16 we will get the 11x/4 term
9x/4+11/16
4x+1| 9x^2+5x. +2
9x^2+9x/4
11x/4. +2
4x+1| 9x^2+5x. +2
9x^2+9x/4
11x/4. +2
11x/4+11/16
21/16
21/16 is the remainder after the long division.
9x^2+5x+2
=(9x/4+11/16)(4x+1)+21/16
to check multiply out the right hand side
=9x^2
+9x/4+11x/4
+11/16+21/16
yep checks out!
or rewriting by dividing by (4x+1)
(9x^2+5x+2)/(4x+1)
=(9x/4+11/16)
=(9x/4+11/16)
+21/[16(4x+1)]