Thanks for that InteGrand.I believe this Q. was asked here before, and answered by Sy123: http://community.boredofstudies.org...1437/intermediate-value-theorem-question.html .
I have another question. What would be the quickest method to do this?
The method I know involves converting the plane to a Cartesian equation and then substituting the x1, x2 and x3 variables of the cartesian equation with the line. This took very long for this question, and I got it wrong...