Find the points of intersection of parabola Y=x^2-7x+23 and the straight line Y=7x-1.

2 answers

using substitution,

x^2 - 7x + 23 = 7x - 1
x^2 - 14x + 24 = 0
(x - 12)(x - 2) = 0
x = 12 or x = 2

if x=12, y = 7(12)-1 = 83
if x=2 , y = 7(2)-1 = 13

they intersect at (12,83) and (2,13)

confirmation here:
look at the first graph

http://www.wolframalpha.com/input/?i=plot+Y%3Dx%5E2-7x%2B23+%2C+Y%3D7x-1+from+0+to+15
Yes?