- #1

naffle

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## Homework Statement

When rx^3 + gx^2 +4x + 1 is divided by x-1, the remainder is 12. When it is divided by x+3, the remainder is -20. Find the values of r and g.

## Homework Equations

## The Attempt at a Solution

r=f(1)

=r(1)^3 + g(1)^2 + 4(1) +5

=r + g +9

r=12

r+g+9=12

r+g= 3

r=f(-3)

=r(-3)^3 + g(-3)^2 + 4(-3) +5

=-27r +9g -7

r=-20

-27r +9g -7=-20

-27 +9g=-13

Then I was just going to use elimination to find r and g.

-27r-27g=-81 (equation 1 multiplied by -27)

-27r+9g=-13

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-36g=-68

g= 1.89

But that answer is wrong.

Is one of my equations wrong or am I going about it incorrectly?

I was able to find the unknown in a equation similar to this, so I'm not sure why I'm having such trouble with this one.

Thanks for any help!