# Math Help - roots question

1. ## roots question

i tried to work out this question but i cant make it
find the value of k for which the equation xsquared-2x/4x+7 = k-1/k+1 has roots equal in magnitude but opposite in sign

2. Originally Posted by clutch
i tried to work out this question but i cant make it
find the value of k for which the equation xsquared-2x/4x+7 = k-1/k+1 has roots equal in magnitude but opposite in sign
Dear clutch,

Please use parentheses while typing your question, so that you make it clear and the helpers here, dont waste time over a wrongly assumed question.

Should your equation read $\frac{x^2 - 2x}{4x + 7} = \frac{k-1}{k+1}$?

3. yes like that tks!
$\frac{x^2 - 2x}{4x + 7} = \frac{k-1}{k+1}
$

4. Ok then...I will give you couple of hints:

1) Do you understand that if you cross multiply and group terms carefully, you will get a quadratic?

2) Do you realize that if a quadratic has "roots equal in magnitude but opposite in sign", then the sum of roots is 0 and thus the coefficient of the linear term in the quadratic is 0?