Year 12s: what will be the first way you research your future options? >>

Further maths polynomials

When x^3+4x^2+kx+6 is divided by (x+5) the remainder is -4. What is k. I was doing polynomials today and got stuck on this question, what would I do to solve it? Would I use the factor/remainder theorem?
Thanks

hope this helps : )

Original post by duckduck..goose

hope this helps : )

whoops! thought the remainder was equal to 4. if its -4 then it should be -5k = 15, and k = -3.

Reply 3

ghostwalker

Original post by Noah00

You'd have been better to post in the maths forum, rather than this umbrella forum which is no where near as heavily frequented.

In answer to your question, yes, the remainder theorem.

If we call your polynomial f(x), then you have f(-5) = -4. Just plug in the numbers and solve for k.