Given that x-3 is a factor of the expression x^3-5x^2+kx-15, show that the value of k is 11.......need help.....

Question

anonymous · Answer

have you heard of the remainder theorem?

anonymous · Answer

well yes......but i couldn't understand the question....

anonymous · Answer

what you do is to substitute 3 (not -3 because you need the 'opposite') into the equation.

$$(3)^3-5(3)^2+k(3)-15$$
now since x-3 is a factor this expresssion ^^ will equal 0 (because there is no remainder)

solve to find d

anonymous · Answer

*k not d

anonymous · Answer

ok...so is it....9-45+3k-15...........and then?

anonymous · Answer

@prasheelasingh make that equal to 0 and then solve for k

anonymous · Answer

k=17?

anonymous · Answer

$$\frac{ 2x+6 }{ 5 }-\frac{x+7}{3}<\frac{3x8}{2}$$ help needed please.......

anonymous · Answer

$$<\frac{3x-8}{2}$$ correction....

anonymous · Answer

@prasheelasingh the first 3 is cubed, not squared