Equation for a straight line

[C++ Programming]

Hi,

I'm trying to animate a box moving from point A to point B. I'm using a .Net timer to
animate but I'm not sure on the math to get the box moving in a straight line. So far
the box finishes moving down before it finishes moving to the right.

Point A
x=9,y=6

Point B
x=291,y=178

I'm not very good at math but I'm thinking the equation should be straight foreward?

Thanks in advance.