Why doesn't -15 divide by 2 in 2x² - 2x - 15 = 0?

[david18]

I'm currently going through some questions and came across quadratic and linear simultaneous equations.

Solve the equation: x + y = 1
x^2 + y^2 = 16

I am not interested in the question itself but rather the explanation the book gives me which says after a couple of steps shows the equation:

2x^2 - 2x -15 = 0

Then it tells me to divide the equation by 2 and says when you divide the equation by 2 you will get:

x^2 - x - 15 = 0

I'm confused because i thought the -15 would also have to divide by two...
is it the book or am i missing something serious here?

 

[neutrino]

If the equation you have provided is right, then it is an error on the part of the author/editor/printer.