Solve, x^(2)-10x+23=0 using the quadratic formula. Someone please help, I do not understand how to solve this!

Step-by-step explanation:

7 books costs $14, etc.  We have points in a line

(7,14)

(8,16)

(9,18)

They're all points on the line y=2x which just means it costs $2 a book.  So 1 book costs $2, 2 cost $4, and 3 cost $6.  We have three new points:

(1,2)

(2,4)

(3,6)

They're all on the same line, y=2x, just closer to the origin than the first three. We plot a point at x=1, y=2,  etc.