Question
The line y=9x-4 intersects the quadratic function y=x^2+7x at one point. What are the coordinates of the point of intersection?
Answers
Steve
that would be where
9x-4 = x^2+7x
x^2-2x+4 = 0
That has no real solutions, so I suspect a typo. See that the graphs do not intersect:
http://www.wolframalpha.com/input/?i=plot+y%3D9x-4+%2C+y+%3D+x^2%2B7x
Now, the line y=9x+4 does intersect the parabola.
9x-4 = x^2+7x
x^2-2x+4 = 0
That has no real solutions, so I suspect a typo. See that the graphs do not intersect:
http://www.wolframalpha.com/input/?i=plot+y%3D9x-4+%2C+y+%3D+x^2%2B7x
Now, the line y=9x+4 does intersect the parabola.