SOLUTION: The line y=3 intersects the graph of y=4x^2+x-1 at the points A and B. The distance between A and B can be written as squareroot m /n, where m and n are positive integers that do n

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: The line y=3 intersects the graph of y=4x^2+x-1 at the points A and B. The distance between A and B can be written as squareroot m /n, where m and n are positive integers that do n      Log On


   

Question 909131: The line y=3 intersects the graph of y=4x^2+x-1 at the points A and B. The distance between A and B can be written as squareroot m /n, where m and n are positive integers that do not share any factors than one. Find the value of m-n. Thank you!
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
The second part of the description seems to mean, sqrt%28m%2Fn%29 and you want m-n; and that distance between x values of the the intersection points is sqrt%28m%2Fn%29.

3=4x%5E2%2Bx-1
4x%5E2%2Bx-4=0
x=%28-1%2B-+sqrt%281%2B16%29%29%2F8
The x values, highlight%28x=%28-1%2B-sqrt%2817%29%29%2F8%29

Distance Between Those x values:
%28%28-1-sqrt%2817%29%29-%28-1%2Bsqrt%2817%29%29%29%2F8
%28-2sqrt%2817%29%29%2F8
-sqrt%2817%29%2F4

I am stopping here because of the lack of clarity in part of your description, but you may be able to understand what you need from the steps presented.