If x=kc and y=kt,then 2y-x =?  Pick.
A) k(t-c)  B) k(c-t)  C) c(k-t)  D) t(k-c)  E) k(2t-c)
Just put in the given values of y and x   2y - x = 2kt - kc   Now take k common   2y - x = k(2t - c)   You get (k(2t-c)) as your answer.
<result>E</result>
If x=kc and y=kt,then 2y-x =?